iSCSI initator clients, dont see same drive changes

[bmcdevitt]

Hey guys, i have 3 servers, connecting to a 800GB drive i created with freenas 8. I got the target portals setup on all of them and connected to the target on all of them.

My problem is when i create a folder on one server, on that drive, i should be able to instantly see it on 2 other servers. But i dont, i create folders and even tried to create 2 with the same name,but it lets me, even when that same name is used by another server on the same target.

My 3 servers are VM's running on ESXI 4

Please help!

Trying to send SQL backups to this drive and than send them off to an offsite backup.

-Ben

 

[bmcdevitt]

I believe the issue is permissions :) this could be a false alarm

 

[pirateghost]

it is a BAAAAAAD idea to attempt read/write operations with multiple hosts attaching to the same iscsi storage, unless you are using true cluster (esx/esxi with VCenter, xen, or Windows Server OS with CLUSTERING enabled, etc)
several lone clients connecting to the same iscsi storage is asking for a corrupt volume.

 

[bmcdevitt]

it is a BAAAAAAD idea to attempt read/write operations with multiple hosts attaching to the same iscsi storage, unless you are using true cluster (esx/esxi with VCenter, xen, or Windows Server OS with CLUSTERING enabled, etc)
several lone clients connecting to the same iscsi storage is asking for a corrupt volume.

what do you suggest than? and isn't this the point of ISCSI and "Network Access Storage"? All that's being written to it is the .bak files from SQL, and they all run at different times.

im trying to give all the servers access, at this point it looks like my best bet is to mount a 800GB VHD to one server, share it out and just have them write to that.

 

[jgreco]

This is a problem we've discussed at length in the past.

Take a look at
http://http://doc.freenas.org/index.php/ISCSI

NOTE: 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 you need to support multiple clients to the same data on a non-clustered filesystem, use CIFS or NFS instead of iSCSI or create multiple iSCSI targets (one per client).

I'm pretty sure that got added after some debate about this last time. iSCSI is a SAN protocol, "storage area network", which means that it is a SCSI device accessed over an IP-based SCSI bus. It is meant for block-level access to a device. It definitely shares it. However, if your filesystem on your PC, like NTFS or UFS/FFS, isn't cluster-aware, that means that it will cache data in memory, and will assume that the contents of the disk aren't being changed out underneath it. This leads to catastrophe. Your ESXi hosts, incidentally, DO use a cluster-aware filesystem called vmfs, and THEY are actually able to share that storage cooperatively. That doesn't help you for what you're trying to do, people usually use NFS or CIFS for that.