Shares are created to make part or all of a pool accessible to other computers on the network. The type of share to create depends on factors like which operating systems are being used by computers on the network, security requirements, and expectations for network transfer speeds.
Shares are created to provide and control access to an area of storage. Before creating shares, making a list of the users that need access to storage data, which operating systems these users are using, whether all users should have the same permissions to the stored data, and whether these users should authenticate before accessing the data is recommended. This information can help determine which type of shares are needed, whether multiple datasets are needed to divide the storage into areas with different access and permissions, and how complex it will be to set up those permission requirements. Note that shares are used to provide access to data. When a share is deleted, it removes access to data but does not delete the data itself.
These types of shares and services are available:
- AFP: Apple File Protocol shares are often used when the client computers all run macOS. Apple has slowly shifted to preferring SMB for modern networks, although Time Machine still requires AFP.
- Unix (NFS): Network File System shares are accessible from macOS, Linux, BSD, and the professional and enterprise versions (but not the home editions) of Windows. This can be are a good choice when the client computers do not all run the same operating system but NFS client software is available for all of them.
- WebDAV: WebDAV shares are accessible using an authenticated web browser (read-only) or WebDAV client running on any operating system.
- SMB: Server Message Block shares, also known as Common Internet File System (CIFS) shares, are accessible by Windows, macOS, Linux, and BSD computers. Access is slower than an NFS share due to the single-threaded design of Samba. SMB provides more configuration options than NFS and is a good choice on a network for Windows systems. However, it is a poor choice if the CPU on the FreeNAS® system is limited; if the CPU is maxed out, upgrade the CPU or consider another type of share.
- Block (iSCSI): Block or iSCSI shares appear as an unformatted disk to clients running iSCSI initiator software or a virtualization solution such as VMware. These are usually used as virtual drives.
Fast access from any operating system can be obtained by configuring the FTP service instead of a share and using a cross-platform FTP file manager application such as Filezilla. Secure FTP can be configured if the data needs to be encrypted.
When data security is a concern and the network users are familiar with SSH command line utilities or WinSCP, consider using the SSH service instead of a share. It is slower than unencrypted FTP due to the encryption overhead, but the data passing through the network is encrypted.
It is generally a mistake to share a pool or dataset with more than one share type or access method. Different types of shares and services use different file locking methods. For example, if the same pool is configured to use both NFS and FTP, NFS will lock a file for editing by an NFS user, but an FTP user can simultaneously edit or delete that file. This results in lost edits and confused users. Another example: if a pool is configured for both AFP and SMB, Windows users can be confused by the “extra” filenames used by Mac files and delete them. This corrupts the files on the AFP share. Pick the one type of share or service that makes the most sense for the types of clients accessing that pool, and use that single type of share or service. To support multiple types of shares, divide the pool into datasets and use one dataset per share.
This section demonstrates configuration and fine-tuning of AFP, NFS, SMB, WebDAV, and iSCSI shares. FTP and SSH configurations are described in Services.
11.1. Apple (AFP) Shares¶
FreeNAS® uses the Netatalk AFP server to share data with Apple systems. This section describes the configuration screen for fine-tuning AFP shares. It then provides configuration examples for configuring Time Machine to back up to a dataset on the FreeNAS® system and for connecting to the share from a macOS client.
Create a share by clicking Sharing ‣ Apple (AFP), then ADD.
New AFP shares are visible in the Sharing ‣ Apple (AFP) menu.
The configuration options shown in Figure 11.1.1 appear after clicking (Options) on an existing share, and selecting the Edit option. The values showing for these options will vary, depending upon the information given when the share was created.
Table 11.1.1 summarizes the options available to fine-tune an AFP share. Leaving these options at the default settings is recommended as changing them can cause unexpected behavior. Most settings are only available with Advanced Mode. Do not change an advanced option without fully understanding the function of that option. Refer to Setting up Netatalk for a more detailed explanation of these options.
|Path||browse button||Browse to the pool or dataset to share. Do not nest additional pools, datasets, or symbolic links beneath this path because Netatalk does not fully support that.|
|Name||string||Enter the pool name that appears in macOS after selecting Go ‣ Connect to server in the Finder menu. Limited to 27 characters and cannot contain a period.|
|Allow list||string||✓||Comma-delimited list of allowed users and/or groups where groupname begins with a
|Deny list||string||✓||Comma-delimited list of denied users and/or groups where groupname begins with a
|Read Only Access||string||✓||Comma-delimited list of users and/or groups who only have read access where groupname begins with a
|Read/Write Access||string||✓||Comma-delimited list of users and/or groups who have read and write access where groupname begins with a
|Time Machine||checkbox||Set to advertise FreeNAS® as a Time Machine disk so it can be found by Macs. Setting multiple shares for Time Machine use is not recommended. When multiple Macs share the same pool, low diskspace issues and intermittently failed backups can occur.|
|Use as home share||checkbox||Set to allow the share to host user home directories. Only one share can be used as the home share.|
|Zero Device Numbers||checkbox||✓||Enable when the device number is not constant across a reboot.|
|No Stat||checkbox||✓||If set, AFP does not stat the pool path when enumerating the pools list. Useful for automounting or pools created by a preexec script.|
|AFP3 UNIX Privs||checkbox||✓||Set to enable Unix privileges supported by OSX 10.5 and higher. Do not enable if the network contains Mac OS X 10.4 clients or lower as they do not support this feature.|
|Default file permissions||checkboxes||✓||Only works with Unix ACLs. New files created on the share are set with the selected permissions.|
|Default directory permissions||checkboxes||✓||Only works with Unix ACLs. New directories created on the share are set with the selected permissions.|
|Default umask||integer||✓||Umask is used for newly created files. Default is 000 (anyone can read, write, and execute).|
|Hosts Allow||string||✓||Enter a list of allowed hostnames or IP addresses. Separate entries with a comma, space, or tab.|
|Hosts Deny||string||✓||Enter a list of denied hostnames or IP addresses. Separate entries with a comma, space, or tab.|
|Auxiliary Parameters||string||Enter any additional afp.conf parameters not covered by other option fields.|
11.1.1. Creating AFP Guest Shares¶
AFP supports guest logins, meaning that macOS users can access the AFP share without requiring their user accounts to first be created on or imported into the FreeNAS® system.
When a guest share is created along with a share that requires authentication, AFP only maps users who log in as guest to the guest share. If a user logs in to the share that requires authentication, permissions on the guest share can prevent that user from writing to the guest share. The only way to allow both guest and authenticated users to write to a guest share is to set the permissions on the guest share to 777 or to add the authenticated users to a guest group and set the permissions to 77x.
Before creating a guest share, go to Services ‣ AFP and click the sliding button to turn on the service. Click (Configure) to open the screen shown in Figure 11.1.2. For Guest Account, use the drop-down to select Nobody, set Guest Access, and click SAVE.
Next, create a dataset for the guest share. Refer to Adding Datasets for more information about dataset creation.
After creating the dataset for the guest share, go to Storage ‣ Pools, click the (Options) button for the dataset, then click Edit Permissions. Complete the fields shown in Figure 11.1.3.
- ACL Type: Select Mac.
- User: Use the drop-down to select Nobody.
- Click SAVE.
To create a guest AFP share:
- Go to Sharing ‣ Apple (AFP) Shares and click ADD.
- Browse to the dataset created for the guest share.
- Fill out the other required fields, then press SAVE.
macOS users can connect to the guest AFP share by clicking Go ‣ Connect to Server. In the example shown in Figure 11.1.4, the user entered afp:// followed by the IP address of the FreeNAS® system.
Click the Connect button. Once connected, Finder opens automatically. The name of the AFP share is displayed in the SHARED section in the left frame and the contents of any data saved in the share is displayed in the right frame.
To disconnect from the pool, click the eject button in the Shared sidebar.
11.1.2. Creating Authenticated and Time Machine Shares¶
macOS includes the Time Machine application which can be used to schedule automatic backups. In this configuration example, a Time Machine user will be configured to backup to an AFP share on a FreeNAS® system. Creating a separate Time Machine share for each user that will be using Time Machine to backup their macOS system to FreeNAS® is recommended. The process for creating an authenticated share for a user is the same as creating a Time Machine share for that user.
Before creating a Time Machine or authenticated share, go to Storage ‣ Pools to make a dataset for the share. For more information about dataset creation, refer to Adding Datasets.
After creating the dataset for the guest share, go to Storage ‣ Pools, click the (Options) button for the dataset, then Edit Permissions.
Enter the following information as shown in Figure 11.1.5.
- ACL Type: Select Mac.
- User: Use the drop-down to select the desired user account. If the user does not yet exist on the FreeNAS® system, go to Accounts ‣ Users to create one. Refer to users in this guide for more information about creating a user.
- Group: Use the drop-down to select the desired group name. If the group does not yet exist on the FreeNAS® system, go to Accounts ‣ Groups to create one. Refer to groups in this guide for more information about creating a group.
- Click SAVE.
To create an authenticated or Time Machine share:
- Go to Sharing ‣ AFP and click ADD.
- Browse to the dataset created for the share.
- When creating a Time Machine share, enable the Time Machine option.
- Fill out the other required fields.
- Click SAVE.
To configure multiple authenticated or Time Machine shares, repeat this process for each user. The new shares appear in Sharing ‣ Apple (AFP).
At this point, it may be desirable to configure a quota for each Time Machine share, to restrict backups from using all of the available space on the FreeNAS® system. The first time Time Machine makes a backup, it will create a full backup after waiting two minutes. It will then create a one hour incremental backup for the next 24 hours, and then one backup each day, each week and each month. Since the oldest backups are deleted when a Time Machine share becomes full, make sure that the quota size is sufficient to hold the desired number of backups. Note that a default installation of macOS is ~21 GiB in size.
To configure a quota, go to Sharing ‣ Apple (AFP), click (Options) on the existing Time Machine share, then Edit. In the example shown in Figure 11.1.6, the Time Machine share name is backup_user1. Enter a value in the Time Machine Quota field, then click SAVE. In this example, the Time Machine share is restricted to 200 GiB.
An alternative is to create a global quota using the instructions in Set up Time Machine for multiple machines with OSX Server-Style Quotas.
To configure Time Machine on the macOS client, go to System Preferences ‣ Time Machine which opens the screen shown in Figure 11.1.7. Click ON and a pop-up menu shows the FreeNAS® system as a backup option. In this example, it is listed as backup_user1 on “freenas”. Highlight the FreeNAS® system and click Use Backup Disk. A connection bar opens and prompts for the user account’s password–in this example, the password that was set for the user1 account.
Time Machine could not complete the backup. The backup disk
image could not be created (error 45) is shown when backing up to the
FreeNAS® system, a sparsebundle image must be created using
Time Machine completed a verification of your backups.
To improve reliability, Time Machine must create a new backup for you.
is shown, follow the instructions in this post
to avoid making another backup or losing past backups.
11.2. Unix (NFS) Shares¶
FreeNAS® supports sharing over the Network File System (NFS). Clients use the mount command to mount the share. Once mounted, the NFS share appears as just another directory on the client system. Some Linux distros require the installation of additional software in order to mount an NFS share. On Windows systems, enable Services for NFS in the Ultimate or Enterprise editions or install an NFS client application.
For performance reasons, iSCSI is preferred to NFS shares when FreeNAS® is installed on ESXi. When considering creating NFS shares on ESXi, read through the performance analysis presented in Running ZFS over NFS as a VMware Store.
Before creating an NFS share, go to Services ‣ NFS and click the sliding button to turn on the service.
Next, go to Storage ‣ Pools to create a dataset for the share. Refer to Adding Datasets for more information about dataset creation.
Create an NFS share by going to Sharing ‣ Unix (NFS) Shares and clicking ADD. Figure 11.2.1 shows an example of creating an NFS share.
For the required Path field, browse to the dataset created for the share. In the Comment field enter a share name, note that if left empty, the share name is the list of selected Path entries. Click the SAVE button to create the share.
Edit an NFS share by going to Sharing ‣ Unix (NFS), clicking the (Options) button for the desired share, then Edit. In the example shown in Figure 11.2.2, the configuration screen is open for the nfs_share1 share.
Table 11.2.1 summarizes the available configuration options in this screen. Some settings are only available by clicking the ADVANCED MODE button.
|Path||browse button||The required full path to the pool or dataset to share. Click ADD ADDITIONAL PATH to configure multiple paths.|
|Comment||string||Set the share name. If left empty, share name is the list of selected Path entries.|
|All dirs||checkbox||Set to allow the client to mount any subdirectory within the Path.|
|Read Only||checkbox||Set to prohibit writing to the share.|
|Quiet||checkbox||✓||Set to inhibit some syslog diagnostics to avoid error messages. See exports(5) for examples.|
|Authorized networks||string||✓||Space-delimited list of allowed networks in network/mask CIDR notation. Example: 184.108.40.206/24. Leave empty to allow all.|
|Authorized Hosts and IP addresses||string||✓||Space-delimited list of allowed IP addresses or hostnames. Leave empty to allow all.|
|Maproot User||drop-down menu||✓||When a user is selected, the root user is limited to the permissions of that user.|
|Maproot Group||drop-down menu||✓||When a group is selected, the root user is also limited to the permissions of that group.|
|Mapall User||drop-down menu||✓||The specified permissions of that user are used by all clients.|
|Mapall Group||drop-down menu||✓||The specified permissions of that group are used by all clients.|
|Security||selection||✓||Only appears if Enable NFSv4 is enabled in Services ‣ NFS ‣ Configure. Choices are sys or these Kerberos options: krb5 (authentication only), krb5i (authentication and integrity), or krb5p (authentication and privacy).|
When creating NFS shares, keep these points in mind:
- Clients will specify the Path when mounting the share.
- The Maproot and Mapall options are exclusive, meaning only one can be used as the web interface does not allow both. The Mapall options supersede the Maproot options. To restrict only the root user permissions, set the Maproot option. To restrict permissions of all users, set the Mapall options.
- Each pool or dataset is considered to be its own filesystem and NFS is not able to cross filesystem boundaries.
- The network and host must be unique per share and per filesystem or
/etc/exportsdoes not act like an ACL, the rule to apply is undefined among overlapping networks or when using the same share with multiple hosts.
- The All dirs option can only be used once per share per filesystem.
To better understand these restrictions, consider a scenario where there are:
- two networks, 10.0.0.0/8 and 220.127.116.11/8
- a ZFS pool named
pool1with 2 datasets named
dataset1contains a directory named
Because of restriction #3, an error is shown when trying to create one NFS share like this:
- Authorized Networks set to 10.0.0.0/8 18.104.22.168/8
- Path set to
Instead, set a Path of
check the All dirs box.
That directory could also be restricted to one of the networks by creating two shares instead:
First NFS share:
- Authorized Networks set to 10.0.0.0/8
- Path set to
Second NFS share:
- Authorized Networks set to 22.214.171.124/8
- Path set to
Note that this requires the creation of two shares. It cannot be done with only one share.
11.2.1. Example Configuration¶
By default, the Mapall fields are not set. This means that when a user connects to the NFS share, the user has the permissions associated with their user account. This is a security risk if a user is able to connect as root as they will have complete access to the share.
A better option is to do this:
- Specify the built-in nobody account to be used for NFS access.
- In the Change Permissions screen of the pool or dataset that is being shared, change the owner and group to nobody and set the permissions according to the desired requirements.
- Select nobody in the Mapall User and Mapall Group drop-down menus for the share in Sharing ‣ Unix (NFS) Shares.
With this configuration, it does not matter which user account connects to the NFS share, as it will be mapped to the nobody user account and will only have the permissions that were specified on the pool or dataset. For example, even if the root user is able to connect, it will not gain root access to the share.
11.2.2. Connecting to the Share¶
The following examples share this configuration:
- The FreeNAS® system is at IP address 192.168.2.2.
- A dataset named
/mnt/pool1/nfs_share1is created and the permissions set to the nobody user account and the nobody group.
- An NFS share is created with these attributes:
- Authorized Networks: 192.168.2.0/24
- All dirs option is enabled
- MapAll User is set to nobody
- MapAll Group is set to nobody
126.96.36.199. From BSD or Linux¶
NFS shares are mounted on BSD or Linux clients with this command executed as the superuser (root) or with sudo:
mount -t nfs 192.168.2.2:/mnt/pool1/nfs_share1 /mnt
- -t nfs specifies the filesystem type of the share
- 192.168.2.2 is the IP address of the FreeNAS® system
- /mnt/pool/nfs_share1 is the name of the directory to be shared, a dataset in this case
- /mnt is the mountpoint on the client system. This must be an existing, empty directory. The data in the NFS share appears in this directory on the client computer.
A successful mounting of the share returns to the command prompt without any status or error messages.
If this command fails on a Linux system, make sure that the nfs-utils package is installed.
This configuration allows users on the client system to copy files to
/mnt (the mount point). All files are owned by
nobody:nobody. Changes to any files or directories in
are written to the FreeNAS® system’s
Settings cannot be changed on the NFS share if it is mounted on any client computers. The umount command is used to unmount the share on BSD and Linux clients. Run it as the superuser or with sudo on each client computer:
188.8.131.52. From Microsoft¶
Windows NFS client support varies with versions and releases. For best results, use Windows (SMB) Shares.
184.108.40.206. From macOS¶
To mount the NFS share from a macOS client, go to Go ‣ Connect to Server. In the Server Address field, enter nfs:// followed by the IP address of the FreeNAS® system, and the name of the pool or dataset being shared by NFS. The example shown in Figure 11.2.3 continues with the example of 192.168.2.2:/mnt/pool1/nfs_share1.
Finder opens automatically after connecting. The IP address of the
FreeNAS® system is displayed in the SHARED section in the left frame
and the contents of the share are displayed in the right frame. In the
example shown in
/mnt/data has one folder named
images. The user can
now copy files to and from the share.
11.2.3. Troubleshooting NFS¶
Some NFS clients do not support the NLM (Network Lock Manager)
protocol used by NFS. This is the case if the client receives an error
that all or part of the file may be locked when a file transfer is
attempted. To resolve this error, add the option
when running the mount command on the client to allow write
access to the NFS share.
If a “time out giving up” error is shown when trying to mount the
share from a Linux system, make sure that the portmapper service is
running on the Linux client. If portmapper is running and timeouts are
still shown, force the use of TCP by including
-o tcp in the
RPC: Program not registered error is shown, upgrade to
the latest version of FreeNAS® and restart the NFS service after the
upgrade to clear the NFS cache.
If clients see “reverse DNS” errors, add the FreeNAS® IP address in the Host name database field of Network ‣ Global Configuration.
If clients receive timeout errors when trying to mount the share, add the client IP address and hostname to the Host name database field in Network ‣ Global Configuration.
Some older versions of NFS clients default to UDP instead of TCP and do not auto-negotiate for TCP. By default, FreeNAS® uses TCP. To support UDP connections, go to Services ‣ NFS ‣ Configure and enable the Serve UDP NFS clients option.
nfsstat -c or
nfsstat -s commands can be helpful
to detect problems from the Shell. A high proportion of retries
and timeouts compared to reads usually indicates network problems.
11.3. WebDAV Shares¶
In FreeNAS®, WebDAV shares can be created so that authenticated users can browse the contents of the specified pool, dataset, or directory from a web browser.
Configuring WebDAV shares is a two step process. First, create the WebDAV shares to specify which data can be accessed. Then, configure the WebDAV service by specifying the port, authentication type, and authentication password. Once the configuration is complete, the share can be accessed using a URL in the format:
- protocol: is either http or https, depending upon the Protocol configured in Services ‣ WebDAV ‣ CONFIGURE.
- IP address: is the IP address or hostname of the FreeNAS® system. Take care when configuring a public IP address to ensure that the network firewall only allows access to authorized systems.
- port_number: is configured in Services ‣ WebDAV ‣ CONFIGURE. If the FreeNAS® system is to be accessed using a public IP address, consider changing the default port number and ensure that the network firewall only allows access to authorized systems.
- share_name: is configured by clicking Sharing ‣ WebDAV Shares, then ADD.
Entering the URL in a web browser brings up an authentication pop-up message. Enter a username of webdav and the password configured in Services ‣ WebDAV ‣ CONFIGURE.
At this time, only the webdav user is supported. For this reason, it is important to set a good password for this account and to only give the password to users which should have access to the WebDAV share.
To create a WebDAV share, go to Sharing ‣ WebDAV Shares and click ADD, which will open the screen shown in Figure 11.3.1.
Table 11.3.1 summarizes the available options.
|Share Name||string||Enter a name for the share.|
|Path||browse button||Browse to the pool or dataset to share.|
|Read Only||checkbox||Set to prohibit users from writing to the share.|
|Change User & Group Ownership||checkbox||Enable to automatically set the share contents to the webdav user and group.|
Click SAVE to create the share. Then, go to Services ‣ WebDAV and click the ⏻ (Power) button to turn on the service.
After the service starts, review the settings in Services ‣ WebDAV ‣ CONFIGURE as they are used to determine which URL is used to access the WebDAV share and whether or not authentication is required to access the share. These settings are described in WebDAV.
11.4. Windows (SMB) Shares¶
FreeNAS® uses Samba to share pools using Microsoft’s SMB protocol. SMB is built into the Windows and macOS operating systems and most Linux and BSD systems pre-install the Samba client in order to provide support for SMB. If the distro did not, install the Samba client using the distro software repository.
The SMB protocol supports many different types of configuration scenarios, ranging from the simple to complex. The complexity of the scenario depends upon the types and versions of the client operating systems that will connect to the share, whether the network has a Windows server, and whether Active Directory is being used. Depending on the authentication requirements, it might be necessary to create or import users and groups.
Samba supports server-side copy of files on the same share with clients from Windows 8 and higher. Copying between two different shares is not server-side. Windows 7 clients support server-side copying with Robocopy.
This chapter starts by summarizing the available configuration options. It demonstrates some common configuration scenarios as well as offering some troubleshooting tips. Reading through this entire chapter before creating any SMB shares is recommended to gain a better understanding of the configuration scenario that meets the specific network requirements.
SMB1 is disabled by default for security. If legacy clients are unable to connect to the share, open Shell, type sysctl freenas.services.smb.config.server_min_protocol=NT1, then restart the SMB service. If legacy clients can then connect to the share, the change can be made permanent by going to Tunables, creating a tunable with a Variable of freenas.services.smb.config.server_min_protocol, a Value of NT1, and a Type of Sysctl.
SMB Tips and Tricks shows helpful hints for configuring and managing SMB networking. The FreeNAS and Samba (CIFS) permissions and Advanced Samba (CIFS) permissions on FreeNAS videos clarify setting up permissions on SMB shares. Another helpful reference is Methods For Fine-Tuning Samba Permissions.
Run smbstatus from the Shell for a list of active connections and users.
Figure 11.4.1 shows the configuration screen that appears after clicking Sharing ‣ Windows (SMB Shares), then ADD.
Table 11.4.1 summarizes the options available when creating a SMB share. Some settings are only configurable after clicking the ADVANCED MODE button. For simple sharing scenarios, ADVANCED MODE options are not needed. For more complex sharing scenarios, only change an ADVANCED MODE option after fully understanding the function of that option. smb.conf(5) provides more details for each configurable option.
|Path||browse button||Select pool or dataset/directory to share.|
|Name||string||Enter a mandatory name for the share.|
|Use as home share||checkbox||Set to allow this share to hold user home directories. Only one share can be the home share. Note that lower case names for user home directories are strongly recommended, as Samba maps usernames to all lower case. For example, the username John will be mapped to a home directory named john. If the Path to the home share includes an upper case username, delete the existing user and recreate it in Accounts ‣ Users with an all lower case Username. Return to Sharing ‣ SMB to create the home share, and select the Path that contains the new lower case username.|
|Default Permissions||checkbox||When enabled, the ACLs grant read and write for owner or group and read-only for others. Only leave unset if creating a share on a system that already has custom ACLs configured.|
|Export Read Only||checkbox||✓||Set to prohibit write access to this share.|
|Browsable to Network Clients||checkbox||✓||When set, users see the contents of /homes, which includes the home directories of other users. When unset, users only see their own home directory.|
|Export Recycle Bin||checkbox||✓||When set, deleted files are moved to a hidden
|Show Hidden Files||checkbox||✓||Set to disable the Windows hidden attribute on a new Unix hidden file. Unix hidden filenames start with
|Allow Guest Access||checkbox||Set to allow access to this share without a password. See SMB service for more information about guest user permissions.|
|Only Allow Guest Access||checkbox||✓||Requires Allow guest access to also be enabled. Forces guest access for all connections.|
|Hosts Allow||string||✓||Enter a list of allowed hostnames or IP addresses. Separate entries with a comma, space, or tab.|
|Hosts Deny||string||✓||Enter a list of denied hostnames or IP addresses. Allowed hosts take Specify ALL and list any hosts from Hosts Allow to have those hosts take precedence.|
|VFS Objects||selection||✓||Adds virtual file system modules to enhance functionality. Table 11.4.2 summarizes the available modules.|
|Periodic Snapshot Task||drop-down menu||✓||Used to configure directory shadow copies on a per-share basis. Select the pre-configured periodic snapshot task to use for the share’s shadow copies. Periodic snapshot must be recursive.|
Here are some notes about ADVANCED MODE settings:
- Hostname lookups add some time to accessing the SMB share. If only using IP addresses, unset the Hostnames Lookups setting in Services ‣ SMB ‣ (Configure).
- When the Browsable to Network Clients option is selected, the share is visible through Windows File Explorer or through net view. When the Use as home share option is selected, deselecting the Browsable to Network Clients option hides the share named homes so that only the dynamically generated share containing the authenticated user home directory will be visible. By default, the homes share and the user home directory are both visible. Users are not automatically granted read or write permissions on browsable shares. This option provides no real security because shares that are not visible in Windows File Explorer can still be accessed with a UNC path.
- If some files on a shared pool should be hidden and inaccessible to users, put a veto files= line in the Auxiliary Parameters field. The syntax for the veto files option and some examples can be found in the smb.conf manual page.
Samba disables NTLMv1 authentication by default for security. Standard configurations of Windows XP and some configurations of later clients like Windows 7 will not be able to connect with NTLMv1 disabled. Security guidance for NTLMv1 and LM network authentication has information about the security implications and ways to enable NTLMv2 on those clients. If changing the client configuration is not possible, NTLMv1 authentication can be enabled by selecting the NTLMv1 auth option in Services ‣ SMB ‣ (Configure).
Table 11.4.2 provides an overview of the available VFS modules. Be sure to research each module before adding or deleting it from the Selected column of the VFS Objects field of the share. Some modules need additional configuration after they are added. Refer to Stackable VFS modules and the vfs_* man pages for more details.
|acl_tdb||Stores NTFS ACLs in a tdb file to enable full mapping of Windows ACLs.|
|acl_xattr||Stores NTFS ACLs in Extended Attributes (EAs) to enable the full mapping of Windows ACLs.|
|aio_fork||Enables async I/O.|
|aio_pthread||Implements async I/O in Samba vfs using a pthread pool instead of the internal Posix AIO interface.|
|audit||Logs share access, connects/disconnects, directory opens/creates/removes, and file opens/closes/renames/unlinks/chmods to syslog.|
|cacheprime||Primes the kernel file data cache.|
|cap||Translates filenames to and from the CAP encoding format, commonly used in Japanese language environments.|
|catia||Improves Mac interoperability by translating characters that are unsupported by Windows.|
|commit||Tracks the amount of data written to a file and synchronizes it to disk when a specified amount accumulates.|
|crossrename||Allows server side rename operations even if source and target are on different physical devices.|
|default_quota||Stores the default quotas that are reported to a windows client in the quota record of a user.|
|dfs_samba4||Distributed file system for providing an alternative name space, load balancing, and automatic failover.|
|dirsort||Sorts directory entries alphabetically before sending them to the client.|
|expand_msdfs||Enables support for Microsoft Distributed File System (DFS).|
|extd_audit||Sends audit logs to both syslog and the Samba log files.|
|fake_acls||Stores file ownership and ACLs as extended attributes.|
|fake_perms||Allows roaming profile files and directories to be set as read-only.|
|fruit||Enhances macOS support by providing the SMB2 AAPL extension and Netatalk interoperability. Automatically loads catia and streams_xattr but read the caveat in NOTE below table.|
|full_audit||Record selected client operations to the system log.|
|linux_xfs_sgid||Used to work around an old Linux XFS bug.|
|media_harmony||Allows Avid editorial workstations to share a network drive.|
|netatalk||Eases the co-existence of SMB and AFP shares.|
|offline||Marks all files in the share with the DOS offline attribute. This can prevent Windows Explorer from reading files just to make thumbnail images.|
|posix_eadb||Provides Extended Attributes (EAs) support so they can be used on filesystems which do not provide native support for EAs.|
|preopen||Useful for video streaming applications that want to read one file per frame.|
|readahead||Useful for Windows Vista clients reading data using Windows Explorer.|
|readonly||Marks a share as read-only for all clients connecting within the configured time period.|
|shadow_copy||Allows Microsoft shadow copy clients to browse shadow copies on Windows shares.|
|shadow_copy_test||Shadow copy testing.|
|shell_snap||Provides shell-script callouts for snapshot creation and deletion operations issued by remote clients using the File Server Remote VSS Protocol (FSRVP).|
|skel_opaque||Implements dummy versions of all VFS modules (useful to VFS module developers).|
|skel_transparent||Implements dummy passthrough functions of all VFS modules (useful to VFS module developers).|
|snapper||Provides the ability for remote SMB clients to access shadow copies of FSRVP snapshots using Windows Explorer.|
|streams_depot||Experimental module to store alternate data streams in a central directory. The association with the primary file can be lost due to inode numbers changing when a directory is copied to a new location. See https://marc.info/?l=samba&m=132542069802160&w=2.|
|streams_xattr||Enables storing of NTFS alternate data streams in the file system.|
|syncops||Ensures metadata operations are performed synchronously.|
|time_audit||Logs system calls that take longer than the number of defined milliseconds.|
|unityed_media||Allows multiple Avid clients to share a network drive.|
|winmsa||Emulate Microsoft’s MoveSecurityAttributes=0 registry option, setting the ACL for file and directory hierarchies to inherit from the parent directory into which they are moved.|
|worm||Controls the writability of files and folders depending on their change time and an adjustable grace period.|
|xattr_tdb||Stores Extended Attributes (EAs) in a tdb file so they can be used on filesystems which do not provide support for EAs.|
|zfs_space||Correctly calculates ZFS space used by the share, including space used by ZFS snapshots, quotas, and resevations. Enabled by default.|
|zfsacl||Provide ACL extensions for proper integration with ZFS. Enabled by default.|
Be careful when using multiple SMB shares, some with and some without fruit. macOS clients negotiate SMB2 AAPL protocol extensions on the first connection to the server, so mixing shares with and without fruit will globally disable AAPL if the first connection occurs without fruit. To resolve this, all macOS clients need to disconnect from all SMB shares and the first reconnection to the server has to be to a fruit-enabled share.
These VFS objects do not appear in the drop-down menu:
- recycle: moves deleted files to the recycle directory instead of deleting them. Controlled by Export Recycle Bin in the SMB share options.
- shadow_copy2: a more recent implementation of
shadow_copy with some additional features.
shadow_copy2 and the associated parameters are automatically added
smb4.confwhen a Periodic Snapshot Task is selected.
11.4.1. Configuring Unauthenticated Access¶
SMB supports guest logins, meaning that users can access the SMB share without needing to provide a username or password. This type of share is convenient as it is easy to configure, easy to access, and does not require any users to be configured on the FreeNAS® system. This type of configuration is also the least secure as anyone on the network can access the contents of the share. Additionally, since all access is as the guest user, even if the user inputs a username or password, there is no way to differentiate which users accessed or modified the data on the share. This type of configuration is best suited for small networks where quick and easy access to the share is more important than the security of the data on the share.
To configure an unauthenticated SMB share:
- Go to Sharing ‣ Windows (SMB) Shares and click ADD.
- Fill out the the fields as shown in Figure 11.4.2.
- Enable the Allow guest access option.
- Press SAVE.
If a dataset for the share has not been created, refer to Adding Datasets to find out more about dataset creation.
The new share appears in Sharing ‣ Windows (SMB) Shares.
Users can now access the share from any SMB client and will not be prompted for their username or password. For example, to access the share from a Windows system, open Explorer and click on Network. For this configuration example, a system named FREENAS appears with a share named insecure_smb. The user can copy data to and from the unauthenticated SMB share.
11.4.2. Configuring Authenticated Access Without a Domain Controller¶
Most configuration scenarios require each user to have their own user account and to authenticate before accessing the share. This allows the administrator to control access to data, provide appropriate permissions to that data, and to determine who accesses and modifies stored data. A Windows domain controller is not needed for authenticated SMB shares, which means that additional licensing costs are not required. However, since there is no domain controller to provide authentication for the network, each user account needs to be created on the FreeNAS® system. This type of configuration scenario is often used in home and small networks as it does not scale well if many users accounts are needed.
Before configuring this scenario, determine which users will need authenticated access. While not required for the configuration, it eases troubleshooting if the username and password that will be created on the FreeNAS® system matches that information on the client system. Next, determine if each user should have their own share to store their own data or if several users will be using the same share. The simpler configuration is to make one share per user as it does not require the creation of groups, adding the correct users to the groups, and ensuring that group permissions are set correctly.
Before creating an authenticated SMB share, go to Storage ‣ Pools to make a dataset for the share. For more information about dataset creation, refer to Adding Datasets.
After creating the dataset, go to Storage ‣ Pools and click the (Options) button for the desired dataset. Click Edit Permissions and fill out the information as shown in Figure 11.4.3.
- ACL Type: Select Windows.
- User: If the user does not yet exist on the FreeNAS® system, go to Accounts ‣ Users to create one. Refer to Users for more information about creating a user. After the user has been created, use the drop-down to select the user account.
- Group: Use the drop-down to select the desired group name. If the group does not yet exist on the FreeNAS® system, go to Accounts ‣ Groups to create one. Refer to Groups for more information about creating a group.
- Click SAVE.
To create an authenticated SMB share, go to Sharing ‣ Windows (SMB) Shares and click ADD, as shown in Figure 11.4.4. Browse to the dataset created for the share and enter a name for the share. Press SAVE to create the share.
To configure multiple authenticated shares, repeat for each user. The new shares are also added to Sharing ‣ Windows (SMB) Shares.
The authenticated share can now be tested from any SMB client. For example, to test an authenticated share from a Windows system, open Explorer and click on Network. For this configuration example, a system named FREENAS appears with a share named smb_user1. After clicking smb_user1, a Windows Security pop-up screen prompts for that user’s username and password. Enter the values that were configured for that share, in this case user user1. After authentication, the user can copy data to and from the SMB share.
To prevent Windows Explorer from hanging when accessing the share, map the share as a network drive. To do this, right-click the share and select Map network drive…. Choose a drive letter from the drop-down menu and click the Finish button.
Note that Windows systems cache a user’s credentials. This can cause
issues when testing or accessing multiple authenticated shares as only
one authentication is allowed at a time. When authenticating to
a share, if problems occur and the username and password are correct,
type cmd in the Search programs and files box and
use the following command to see if the share is already authenticated.
In this example, the user has already authenticated to the
net use New connections will be remembered. Status Local Remote Network ------------------------------------------------------------------------ OK \\FREENAS\smb_user1 Microsoft Windows Network The command completed successfully.
To clear the cache:
net use * /DELETE You have these remote connections: \\FREENAS\smb_user1 Continuing will cancel the connections. Do you want to continue this operation? <Y/N> [N]: y
An additional warning is shown if the share is currently open in Explorer:
There are open files and/or incomplete directory searches pending on the connection to \\FREENAS|smb_user1. Is it OK to continue disconnecting and force them closed? <Y/N> [N]: y The command completed successfully.
The next time a share is accessed with Explorer, a prompt to authenticate appears.
11.4.3. Configuring Shadow Copies¶
Shadow Copies, also known as the Volume Shadow Copy Service (VSS) or Previous Versions, is a Microsoft service for creating volume snapshots. Shadow copies can be used to restore previous versions of files from within Windows Explorer. Shadow Copy support is built into Vista and Windows 7. Windows XP or 2000 users need to install the Shadow Copy client.
When a periodic snapshot task is created on a ZFS pool that is configured as a SMB share in FreeNAS®, it is automatically configured to support shadow copies.
Before using shadow copies with FreeNAS®, be aware of the following caveats:
- If the Windows system is not fully patched to the latest service pack, Shadow Copies may not work. If no previous versions of files to restore are visible, use Windows Update to ensure the system is fully up-to-date.
- Shadow copy support only works for ZFS pools or datasets. This means that the SMB share must be configured on a pool or dataset, not on a directory.
- Datasets are filesystems and shadow copies cannot traverse filesystems. To see the shadow copies in the child datasets, create separate shares for them.
- Shadow copies will not work with a manual snapshot. Creating a periodic snapshot task for the pool or dataset being shared by SMB or a recursive task for a parent dataset is recommended.
- The periodic snapshot task should be created and at least one snapshot should exist before creating the SMB share. If the SMB share was created first, restart the SMB service in Services.
- Appropriate permissions must be configured on the pool or dataset being shared by SMB.
- Users cannot delete shadow copies on the Windows system due to the way Samba works. Instead, the administrator can remove snapshots from the FreeNAS® web interface. The only way to disable shadow copies completely is to remove the periodic snapshot task and delete all snapshots associated with the SMB share.
To configure shadow copy support, use the instructions in Configuring Authenticated Access Without a Domain Controller to create the desired number of shares. In this configuration example, a Windows 7 computer has two users: user1 and user2. For this example, two authenticated shares are created so that each user account has their own share. The first share is named user1 and the second share is named user2. Then:
- Go to
Tasks ‣ Periodic Snapshot Tasks
and click ADD to create at least one periodic snapshot task.
There are two options for snapshot tasks. One is to create a
snapshot task for each user’s dataset. In this example the datasets
/mnt/volume1/user2. Another option is to create one periodic snapshot task for the entire volume,
/mnt/volume1in this case. Before continuing to the next step, confirm that at least one snapshot for each defined task is displayed in the Storage ‣ Snapshots tab. When creating the schedule for the periodic snapshot tasks, keep in mind how often the users need to access modified files and during which days and time of day they are likely to make changes.
- Go to
Sharing ‣ Windows (SMB) Shares and click
(Options) on an existing share. Click Edit then
ADVANCED MODE. Use the Periodic Snapshot Task
drop-down menu to select the periodic snapshot task to use for that
share. Repeat for each share being configured as a shadow copy. For
this example, the share named
/mnt/pool1/user1is configured to use a periodic snapshot task that was configured to take snapshots of the
/mnt/pool1/user1dataset and the share named
/mnt/pool1/user2is configured to use a periodic snapshot task that was configured to take snapshots of the
- Verify that the SMB service is running in Services.
Figure 11.4.5 provides an example of using shadow copies while logged in as user1 on the Windows system. In this example, the user right-clicked modified file and selected Restore previous versions from the menu. This particular file has three versions: the current version, plus two previous versions stored on the FreeNAS® system. The user can choose to open one of the previous versions, copy a previous version to the current folder, or restore one of the previous versions, overwriting the existing file on the Windows system.
11.5. Block (iSCSI)¶
iSCSI is a protocol standard for the consolidation of storage data. iSCSI allows FreeNAS® to act like a storage area network (SAN) over an existing Ethernet network. Specifically, it exports disk devices over an Ethernet network that iSCSI clients (called initiators) can attach to and mount. Traditional SANs operate over fibre channel networks which require a fibre channel infrastructure such as fibre channel HBAs, fibre channel switches, and discrete cabling. iSCSI can be used over an existing Ethernet network, although dedicated networks can be built for iSCSI traffic in an effort to boost performance. iSCSI also provides an advantage in an environment that uses Windows shell programs; these programs tend to filter “Network Location” but iSCSI mounts are not filtered.
Before configuring the iSCSI service, be familiar with this iSCSI terminology:
CHAP: an authentication method which uses a shared secret and three-way authentication to determine if a system is authorized to access the storage device and to periodically confirm that the session has not been hijacked by another system. In iSCSI, the initiator (client) performs the CHAP authentication.
Mutual CHAP: a superset of CHAP in that both ends of the communication authenticate to each other.
Initiator: a client which has authorized access to the storage data on the FreeNAS® system. The client requires initiator software to initiate the connection to the iSCSI share.
Target: a storage resource on the FreeNAS® system. Every target has a unique name known as an iSCSI Qualified Name (IQN).
Internet Storage Name Service (iSNS): protocol for the automated discovery of iSCSI devices on a TCP/IP network.
Extent: the storage unit to be shared. It can either be a file or a device.
Portal: indicates which IP addresses and ports to listen on for connection requests.
LUN: Logical Unit Number representing a logical SCSI device. An initiator negotiates with a target to establish connectivity to a LUN. The result is an iSCSI connection that emulates a connection to a SCSI hard disk. Initiators treat iSCSI LUNs as if they were a raw SCSI or SATA hard drive. Rather than mounting remote directories, initiators format and directly manage filesystems on iSCSI LUNs. When configuring multiple iSCSI LUNs, create a new target for each LUN. Since iSCSI multiplexes a target with multiple LUNs over the same TCP connection, there can be TCP contention when more than one target accesses the same LUN. FreeNAS® supports up to 1024 LUNs.
In FreeNAS®, iSCSI is built into the kernel. This version of iSCSI supports Microsoft Offloaded Data Transfer (ODX), meaning that file copies happen locally, rather than over the network. It also supports the VAAI (vStorage APIs for Array Integration) primitives for efficient operation of storage tasks directly on the NAS. To take advantage of the VAAI primitives, create a zvol using the instructions in Adding Zvols and use it to create a device extent, as described in Extents.
To configure iSCSI:
- Review the target global configuration parameters.
- Create at least one portal.
- Determine which hosts are allowed to connect using iSCSI and create an initiator.
- Decide if authentication will be used, and if so, whether it will be CHAP or mutual CHAP. If using authentication, create an authorized access.
- Create a target.
- Create either a device or a file extent to be used as storage.
- Associate a target with an extent.
- Start the iSCSI service in Services.
The rest of this section describes these steps in more detail.
11.5.1. Target Global Configuration¶
Sharing ‣ Block (iSCSI) ‣ Target Global Configuration, shown in Figure 11.5.1, contains settings that apply to all iSCSI shares. Table 11.5.1 summarizes the settings that are configured in the Target Global Configuration screen.
Some built-in values affect iSNS usage. Fetching of allowed initiators from iSNS is not implemented, so target ACLs must be configured manually. To make iSNS registration useful, iSCSI targets should have explicitly configured port IP addresses. This avoids initiators attempting to discover unconfigured target portal addresses like 0.0.0.0.
The iSNS registration period is 900 seconds. Registered Network Entities not updated during this period are unregistered. The timeout for iSNS requests is 5 seconds.
|Base Name||string||See the “Constructing iSCSI names using the iqn. format” section of RFC 3721 if unfamiliar with this format.|
|ISNS Servers||string||Enter the hostnames or IP addresses of ISNS servers to be registered with iSCSI targets and portals of the system. Separate each entry with a space.|
|Pool Available Space Threshold||integer||Enter the percentage of free space to in the pool. When this percentage is reached, the system issues an alert, but only if zvols are used. See VAAI Threshold Warning for more information.|
A portal specifies the IP address and port number to be used for iSCSI connections. Go to Sharing ‣ Block (iSCSI) ‣ Portals and click ADD to display the screen shown in Figure 11.5.2.
Table 11.5.2 summarizes the settings that can be configured when adding a portal. To assign additional IP addresses to the portal, click the link Add extra Portal IP.
|Comment||string||Enter an optional description. Portals are automatically assigned a numeric group ID.|
|Discovery Auth Method||drop-down menu||iSCSI supports multiple authentication methods that are used by the target to discover valid devices. None allows anonymous discovery while CHAP and Mutual CHAP both require authentication.|
|Discovery Auth Group||drop-down menu||Select a user created in Authorized Access if the Discovery Auth Method is set to CHAP or Mutual CHAP.|
|IP address||drop-down menu||Select the IPv4 or IPv6 address associated with an interface or the wildcard address of 0.0.0.0 (any interface).|
|Port||integer||TCP port used to access the iSCSI target. Default is 3260.|
FreeNAS® systems with multiple IP addresses or interfaces can use a portal to provide services on different interfaces or subnets. This can be used to configure multi-path I/O (MPIO). MPIO is more efficient than a link aggregation.
If the FreeNAS® system has multiple configured interfaces, portals can also be used to provide network access control. For example, consider a system with four interfaces configured with these addresses:
A portal containing the first two IP addresses (group ID 1) and a portal containing the remaining two IP addresses (group ID 2) could be created. Then, a target named A with a Portal Group ID of 1 and a second target named B with a Portal Group ID of 2 could be created. In this scenario, the iSCSI service would listen on all four interfaces, but connections to target A would be limited to the first two networks and connections to target B would be limited to the last two networks.
Another scenario would be to create a portal which includes every IP address except for the one used by a management interface. This would prevent iSCSI connections to the management interface.
The next step is to configure authorized initiators, or the systems which are allowed to connect to the iSCSI targets on the FreeNAS® system. To configure which systems can connect, go to Sharing ‣ Block (iSCSI) ‣ Initiators and click ADD as shown in Figure 11.5.3.
Table 11.5.3 summarizes the settings that can be configured when adding an initiator.
|Initiators||string||Use ALL keyword or a list of initiator hostnames separated by spaces.|
|Authorized Networks||string||Network addresses that can use this initiator. Use
|Comment||string||Notes or a description of the initiator.|
In the example shown in Figure 11.5.4, two groups are created. Group 1 allows connections from any initiator on any network. Group 2 allows connections from any initiator on the 10.10.1.0/24 network. Click (Options) on an initiator entry to display its Edit and Delete buttons.
Attempting to delete an initiator causes a warning that indicates if any targets or target/extent mappings depend upon the initiator. Confirming the delete causes these to be deleted also.
11.5.4. Authorized Accesses¶
When using CHAP or mutual CHAP to provide authentication, creating an authorized access is recommended. Do this by going to Sharing ‣ Block (iSCSI) ‣ Authorized Access and clicking ADD. The screen is shown in Figure 11.5.5.
This screen sets login authentication. This is different from discovery authentication which is set in Global Configuration.
Table 11.5.4 summarizes the settings that can be configured when adding an authorized access:
|Group ID||integer||Allows different groups to be configured with different authentication profiles. Example: all users with a Group ID of 1 will inherit the authentication profile associated with Group 1|
|User||string||Enter name of user account to create for CHAP authentication with the user on the remote system. Many initiators default to using the initiator name as the user.|
|Secret||string||Enter and confirm a password for User. Must be between 12 and 16 characters.|
|Peer User||string||Only input when configuring mutual CHAP. In most cases it will need to be the same value as User.|
|Peer Secret||string||Enter and confirm the mutual secret password which must be different than the Secret. Required if Peer User is set.|
CHAP does not work with GlobalSAN initiators on macOS.
New authorized accesses are visible from the Sharing ‣ Block (iSCSI) ‣ Authorized Access menu. In the example shown in Figure 11.5.6, three users (test1, test2, and test3) and two groups (1 and 2) have been created, with group 1 consisting of one CHAP user and group 2 consisting of one mutual CHAP user and one CHAP user. Click an authorized access entry to display its Edit and Delete buttons.
Next, create a Target by going to Sharing ‣ Block (iSCSI) ‣ Targets and clicking ADD as shown in Figure 11.5.7. A target combines a portal ID, allowed initiator ID, and an authentication method. Table 11.5.5 summarizes the settings that can be configured when creating a Target.
An iSCSI target creates a block device that may be accessible to multiple initiators. A clustered filesystem is required on the block device, such as VMFS used by VMware ESX/ESXi, in order for multiple initiators to mount the block device read/write. If a traditional filesystem such as EXT, XFS, FAT, NTFS, UFS, or ZFS is placed on the block device, care must be taken that only one initiator at a time has read/write access or the result will be filesystem corruption. If multiple clients need access to the same data on a non-clustered filesystem, use SMB or NFS instead of iSCSI, or create multiple iSCSI targets (one per client).
|Target Name||string||Required value. Base name will be appended automatically if it does not start with iqn.|
|Target Alias||string||Enter an optional user-friendly name.|
|Portal Group ID||drop-down menu||Leave empty or select number of existing portal to use.|
|Initiator Group ID||drop-down menu||Select which existing initiator group has access to the target.|
|Auth Method||drop-down menu||Choices are: None, Auto, CHAP, or Mutual CHAP.|
|Authentication Group number||drop-down menu||Select None or an integer. This number represents the number of existing authorized accesses.|
iSCSI targets provide virtual access to resources on the FreeNAS® system. Extents are used to define resources to share with clients. There are two types of extents: device and file.
Device extents provide virtual storage access to zvols, zvol snapshots, or physical devices like a disk, an SSD, a hardware RAID volume, or a HAST device.
File extents provide virtual storage access to an individual file.
For typical use as storage for virtual machines where the virtualization software is the iSCSI initiator, device extents with zvols provide the best performance and most features. For other applications, device extents sharing a raw device can be appropriate. File extents do not have the performance or features of device extents, but do allow creating multiple extents on a single filesystem.
Virtualized zvols support all the FreeNAS® VAAI primitives and are recommended for use with virtualization software as the iSCSI initiator.
The ATS, WRITE SAME, XCOPY and STUN, primitives are supported by both file and device extents. The UNMAP primitive is supported by zvols and raw SSDs. The threshold warnings primitive is fully supported by zvols and partially supported by file extents.
Virtualizing a raw device like a single disk or hardware RAID volume limits performance to the abilities of the device. Because this bypasses ZFS, such devices do not benefit from ZFS caching or provide features like block checksums or snapshots.
Virtualizing a zvol adds the benefits of ZFS, such as read and write cache. Even if the client formats a device extent with a different filesystem, the data still resides on a ZFS pool and benefits from ZFS features like block checksums and snapshots.
For performance reasons and to avoid excessive fragmentation, keep the used space of the pool below 50% when using iSCSI. The capacity of an existing extent can be increased as shown in Growing LUNs.
To add an extent, go to
Sharing ‣ Block (iSCSI) ‣ Extents
and click ADD. In the example shown in
the device extent is using the
export zvol that was previously
created from the
Table 11.5.6 summarizes the settings that can be configured when creating an extent. Note that file extent creation fails unless the name of the file to be created is appended to the pool or dataset name.
|Extent name||string||Enter the extent name. If the Extent size is not 0, it cannot be an existing file within the pool or dataset.|
|Extent type||drop-down menu||Select from File or Device.|
|Path to the extent||browse button||Only appears if File is selected. Browse to an existing file and use 0 as the Extent size, or browse to the pool or dataset, click Close, append the Extent Name to the path, and specify a value in Extent size. Extents cannot be created inside the jail root directory.|
|Extent size||integer||Only appears if File is selected. If the size is specified as 0, the file must already exist and the actual file size will be used. Otherwise, specify the size of the file to create.|
|Device||drop-down menu||Only appears if Device is selected. Select the unformatted disk, controller, zvol, zvol snapshot, or HAST device.|
|Logical block size||drop-down menu||Only override the default if the initiator requires a different block size.|
|Disable physical block size reporting||checkbox||Set if the initiator does not support physical block size values over 4K (MS SQL). Setting can also prevent constant block size warnings when using this share with ESXi.|
|Available space threshold||string||Only appears if File or a zvol is selected. When the specified percentage of free space is reached, the system issues an alert. See VAAI Threshold Warning.|
|Comment||string||Enter an optional comment.|
|Enable TPC||checkbox||If enabled, an initiator can bypass normal access control and access any scannable target. This allows xcopy operations otherwise blocked by access control.|
|Xen initiator compat mode||checkbox||Set this option when using Xen as the iSCSI initiator.|
|LUN RPM||drop-down menu||Do NOT change this setting when using Windows as the initiator. Only needs to be changed in large environments where the number of systems using a specific RPM is needed for accurate reporting statistics.|
|Read-only||checkbox||Set this option to prevent the initiator from initializing this LUN.|
11.5.7. Associated Targets¶
The last step is associating an extent to a target by going to Sharing ‣ Block (iSCSI) ‣ Associated Targets and clicking ADD. The screen is shown in Figure 11.5.9. Use the drop-down menus to select the existing target and extent. Click SAVE to add an entry for the LUN.
Table 11.5.7 summarizes the settings that can be configured when associating targets and extents.
|Target||drop-down menu||Select an existing target.|
|LUN ID||integer||Type a value between 0 and 1023. Note that some initiators expect a a value below 256. Enter 0 to statically assign the next available ID.|
|Extent||drop-down menu||Select an existing extent.|
Always associating extents to targets in a one-to-one manner is recommended, even though the web interface will allow multiple extents to be associated with the same target.
Each LUN entry has Edit and Delete buttons for modifying the settings or deleting the LUN entirely. A verification popup appears when the Delete button is clicked. If an initiator has an active connection to the LUN, it is indicated in red text. Clearing the initiator connections to a LUN before deleting it is recommended.
After iSCSI has been configured, remember to start the service in Services ‣ iSCSI by clicking the ⏻ (Power) button.
11.5.8. Connecting to iSCSI¶
To access the iSCSI target, clients must use iSCSI initiator software.
An iSCSI Initiator client is pre-installed with Windows 7. A detailed how-to for this client can be found here. A client for Windows 2000, XP, and 2003 can be found here. This how-to shows how to create an iSCSI target for a Windows 7 system.
Mac OS X does not include an initiator. globalSAN is a commercial, easy-to-use Mac initiator.
BSD systems provide command line initiators: iscontrol(8) comes with FreeBSD versions 9.x and lower, iscsictl(8) comes with FreeBSD versions 10.0 and higher, iscsi-initiator(8) comes with NetBSD, and iscsid(8) comes with OpenBSD.
Some Linux distros provide the command line utility iscsiadm from Open-iSCSI. Use a web search to see if a package exists for the distribution should the command not exist on the Linux system.
If a LUN is added while iscsiadm is already connected, it will not see the new LUN until rescanned with iscsiadm -m node -R. Alternately, use iscsiadm -m discovery -t st -p portal_IP to find the new LUN and iscsiadm -m node -T LUN_Name -l to log into the LUN.
Instructions for connecting from a VMware ESXi Server can be found at How to configure FreeNAS 8 for iSCSI and connect to ESX(i). Note that the requirements for booting vSphere 4.x off iSCSI differ between ESX and ESXi. ESX requires a hardware iSCSI adapter while ESXi requires specific iSCSI boot firmware support. The magic is on the booting host side, meaning that there is no difference to the FreeNAS® configuration. See the iSCSI SAN Configuration Guide for details.
The VMware firewall only allows iSCSI connections on port 3260 by default. If a different port has been selected, outgoing connections to that port must be manually added to the firewall before those connections will work.
If the target can be seen but does not connect, check the Discovery Auth settings in Target Global Configuration.
If the LUN is not discovered by ESXi, make sure that promiscuous mode is set to Accept in the vSwitch.
11.5.9. Growing LUNs¶
The method used to grow the size of an existing iSCSI LUN depends on whether the LUN is backed by a file extent or a zvol. Both methods are described in this section.
Enlarging a LUN with one of the methods below gives it more unallocated space, but does not automatically resize filesystems or other data on the LUN. This is the same as binary-copying a smaller disk onto a larger one. More space is available on the new disk, but the partitions and filesystems on it must be expanded to use this new space. Resizing virtual disk images is usually done from virtual machine management software. Application software to resize filesystems is dependent on the type of filesystem and client, but is often run from within the virtual machine. For instance, consider a Windows VM with the last partition on the disk holding an NTFS filesystem. The LUN is expanded and the partition table edited to add the new space to the last partition. The Windows disk manager must still be used to resize the NTFS filesystem on that last partition to use the new space.
220.127.116.11. Zvol Based LUN¶
To grow a zvol-based LUN, go to Storage ‣ Pools, click (Options) on the zvol to be grown, then click Edit zvol. In the example shown in Figure 11.5.10, the current size of the zvol named zvol1 is 4 GiB.
Enter the new size for the zvol in the Size for this zvol field and click SAVE. The new size for the zvol is immediately shown in the Used column of the Storage ‣ Pools table.
The web interface does not allow reducing the size of the zvol, as doing so could result in loss of data. It also does not allow increasing the size of the zvol past 80% of the pool size.
18.104.22.168. File Extent Based LUN¶
To grow a file extent-based LUN:
Services ‣ iSCSI ‣ CONFIGURE ‣ Extents.
Click (Options), then Edit. Ensure the
Extent Type is set to file and enter the
Path to the extent.
Open the Shell to grow the file extent. This example
/mnt/pool1/data by 2 GiB:
truncate -s +2g /mnt/pool1/data
Return to Services ‣ iSCSI ‣ CONFIGURE ‣ Extents, click (Options) on the desired file extent, then click Edit. Set the size to 0 as this causes the iSCSI target to use the new size of the file.