iscsi configuration recommandation

[Claude Durocher]

We need to build a reliable and performant NAS server for vm storage (mostly linux servers but also some Windows servers running on oVirt).

We'll probably be running 20-30 vms on each of our Freenas box wich have the follwing specs :

HP Proliant (Xeon E5-2670 CPU), 64 GB RAM, 2x10 GB nics, 2 x 300 GB RAID1 drives for the freenas OS, 6 x 1.2 TB 10k RPM SAS drives for the storage of the vm

Here's what we think would be a good config (with freenas 9.10):

- Use iScsi (seems like the way to go instead of NFS)
- Use multipath
- Use MTU of 9000
- Use a RAID 10 like config (3 raid 1 vols. in stripes) so we are left with 3.6 TB of usable disk space

My questions are :

1- Should sync writes be activated for iScsi? If so, should we have ZIL logs on some additional SSD drives? Any recommandation for size or partition size of the SSD?
2- When we create a zvol, we get an error if we try to assign more than 80% of the available space. I also read that when using iScsi we should not go over 50% of disk space : I'm totally confused here. Does this mean that with my 6 drives, I'll be left with only 1.8 TB of storage?
3- Any other advices to improve this configuration?

 

[dlavigne]

Were you able to find the answers to your questions?

 

[jgreco]

Were you able to find the answers to your questions?

You'd hope so, with me going on at length to the answers to all those questions on nearly a daily basis, or better yet, in stickies.