Building a FreeNAS Server - thoughts, suggestions and comments

[Treebeard]

Hi all,

I'm planning on building a FreeNAS-based server for the purpose of iSCSI storage. It'll be serving two Hyper-V failover cluster nodes.

As far as the FreeNAS box goes, I've been allowed a budget of £3,500 and have come up with the following important bits:

Asus Z9PE-D16 server mainboard
2x Intel Xeon E5-2620 2.0GHz CPUs
16GB RAM
16x 1TB Seagate ST1000NM0001 Constellation ES HDDs
Adaptec 71605 or 51645 RAID card

I haven't been able to find the Adaptec RAID card in the FreeBSD hardware compatibility list, would this pose a problem? I don't want to buy £500 worth of RAID card only for it to not work...

I would like to use ZFS for the storage, what would be the best way of configuring the drives? Should I put the RAID card into SATA-mode and use a form of RAIDZ, or is there a better way?

I've not used FreeNAS extensively, so I'm completely open to suggestions and comments.

Cheers,
Tom

 

[cyberjock]

Use what everyone else who asks for help with RAID cards uses.. IBM M1015. It's 8 ports(so you'll need 2) and it should be less than $200 for two! Not sure what that translates to in your currency, but I'm sure far less than your limit.

For your function, I'd consider going with 32GB. Also if you search the forum iSCSI isn't exactly a "great" fit for ZFS. You should read up on other threads with ZFS and iSCSI. There can be long term performance killing issues. Just make sure you know this going in. It can be mitigated if you are devoted to fixing the performance(again.. read the threads).

I'm not sure how many users you plan to have, but unless you plan to have more than 10 busy users I might not go dual processor unless you plan to run stuff in the jail that is CPU intensive. I have a first gen low end i7 that can do over 800MB/sec with the only tuning being enabling the Autotune feature. Your bottleneck will certainly be your network cards, so whatever performance you could do beyond Gb speeds is pretty much wasted. You really don't need a super powerful processor to get amazing performance. You just have to buy compatible hardware and enough RAM.

Edit: Let me expand a little. If you are using Samba it will be more important to have higher frequency than more cores since Samba is single threaded. If you plan to use Samba(CIFS/Windows Shares) then you should look for higher frequency and perhaps less cores if your budget starts getting too big. For your application I'd get everything but just 1 CPU at a higher frequency. If you start seeing all of your cores maxing out later you can always get a second one.

Also that board has a quad port i350 NIC. It looks like starting with 8.3 it works if you read ticket 1763 and add that tunable. That's easy to add via the GUI after you install it so don't worry about how difficult that may be. The FreeNAS manual can also help you figure out how to add tunables.

 

[Treebeard]

Thanks for the info, I've done quite a lot of researching iSCSI and ZFS (even found a few of your posts!), so I definitely need to make a decision whether ZFS and iSCSI is the best match.

By "going with 32GB", I presume you mean RAM? I don't mind having to perform a bit of maintenance (obviously being able to install it and leave it would be ideal, but can't have everything!), do you have any examples? I read a few things about Copy on Write reducing performance, is that along the right lines?

We have about 70 users who will be accessing virtual machines on the cluster during the day, but I don't think I would consider the cluster "busy". I only want to use FreeNAS as an iSCSI target, no plans to use Samba directly. The closest thing would be shares via the VMs hosted in the cluster, which would be using FreeNAS as the storage. As performance bottlenecks go, I could think about making the backend SAN 10Gbit if it's not too expensive...

 

[cyberjock]

I did mean 32GB of RAM. If you start with ZFS and it doesn't pan out you could switch to UFS later.

10Gb NICs start at about $200-300 and I'm not sure they are supported by FreeNAS. I thought there was a message in the manual that 10Gb was not supported but I couldn't find it just now. /shrug

 

[jgreco]

Based on the symbols in the kernel, it appears to me that

Code:

ixgb(4)                  - Intel(R) PRO/10GbE Ethernet driver for the FreeBSD operating system
ixgbe(4)                 - Intel(R) 10Gb Ethernet driver for the FreeBSD operating system

are both available. Based on the contents of /boot/kernel/if_cxgb.o, it also appears

Code:

cxgb(4)                  - Chelsio T3 10 Gigabit Ethernet adapter driver

is also available as a loadable module.