FreeNAS as XenServer's Storage Repo

[Amu W Ramappa]

First let me start this thread by thanking the amazing FreeNAS team who has been very helpful in the past, esepcially @cyberjock

At my work place we are looking at replacing our aging HP G5 servers with a virtualized blade server running XenServer as the host OS.

We currently have two FreeNAS box one for the primary storage and one for just backup.
Our primary NAS hardware spec is as follows:

• SuperMicro X10SRL-F
• Intel(R) Xeon(R) CPU E5-2620 v3
  
• 4x16GB ECC DDR4 memory
• On-board 1GB NICs (considering replacing them with Chelsio 10G card)
• 6x4TB WD Red on RAIDz2 with extra 4TB as a spare

We are primarily using the above box on Windows environment with SMB shares.

I'm currently considering using the FreeNAS box as the storage repository for the XenServers' VMs that we'll be creating on our HPE Blade System.

What's the recommended setup for this? I'v read the forums about ESXI and NFS and how the sync write is slow.

But, I would love to hear from the experts on the recommended setup.

Also, I'm thinking of upgrading our switch to a Planet Tech GS 2240-48T4X which has 4 10G SFP+ ports and is affordable for us. So, we're considering replacing our HP1820 48 port with this switch. Please let me know if this switch is not a good options for FreeNAS or for just anything. :)

Also considering getting the Cisco Twinax cable and Chelsio T540-CR2 for the FreeNAS. Any suggestions or red flags on this combination?

Thank you in advance!

 

[m0nkey_]

Here's a couple of points I've picked up with regards to using FN as ESXI/Xen storage:

• Don't go over 50% utilization on the pool. Going over will give you a performance hit.
  
• Configure a SLOG device (typically a mirrored SSDs) to speed up synchronous writes.
• Consider using iSCSI instead of NFS for your data store. This will help with performance.
• Ensure your FN server has as much RAM as possible if using iSCSI.

 

[tvsjr]

Please do some searching and reading on the forums. Some/most of the advice applicable to VMware and Hyper-V will be useful to you.

Right off the bat:
Read up on performance and IOPS. In a VM environment, IOPS (I/O operations per second) are as important if not more important than bulk throughput. With a single 6-disk vdev, you'll get the effctive IOPS of one drive. Striped mirrors is the strongly recommended configuration... the more vdevs, the better.
Assuming your data is important to you, you will need to run sync writes, so you'll want a dedicated SLOG device. Plenty of posts on this topic, but you're typically looking for a higher-end Intel data-center grade SSD (or NVMe if you can afford it) with substantial write endurance.

You should also consider the merits of FreeNAS or another centralized storage solution versus direct-attached storage. If you aren't doing fancy stuff like vMotion, where having a central file store is important, you may actually be better off going with regular rack-mount servers with local storage in RAID10. There's nothing wrong with using FreeNAS for VM storage (I do), but any central storage solution will add substantial complexity - make sure you actually need it.