Options for vdev setup.

[ChrisHH]

I plan to redeploy my SuperMicro server with FreeNAS and need some advice on the best way to configure the drives.

Currently have the following hardware:

192GB ECC RAM
1TB Samsung 970 EVO NVME
18 x 6TB 7200rpm NAS drives
SuperMicro 846 24-bay chasis

My thoughts are to either:

1) 3 x 6 raidz2 vdevs in a pool + 1TB NVMe l2arc
2) buy 2 more 6TB drives and do 2 x 10 raidz2 vdevs in a pool + 1TB NVME l2arc
3) 1 x 18 raidz2 vdev in a pool + 1TB NVMe l2ard (can buy a additional drive and run raidz3)

I like the first option as it gives me up to a 6 disk loss (2 per vdev) before the pool is dead. Spreads the IO over multiple vdevs. Has a better ratio of parity of 2:1 as opposed to 4:1 and 8:1.

I have a secondary SuperMicro 45-bay JBOD enclosure for expansion so this configuration would be permanent for the life of the equipment. I could add additional vdevs to it in 6, 10 or 18 disk chunks down the road.

 

[sretalla]

Option 1 seems reasonable to me. If you want to add VDEVs later and you rely on the IO performance of the 3 VDEVs, be prepared to clear and restore your data to the newly configured pool after adding VDEVs to avoid the performance hit of a new empty VDEV getting all the love from ZFS.