Hello all!
So I currently have a SCALE setup in an 8 Bay Enclosure with 6 8TiB drives.
I currently have them configured as two RAID Z1 vdevs, the system drive and a ssd cache.
Would anyone recommend against this topography? I’ve seen RAID Z1 is discouraged, should I move to just letting TrueNAS take care of it and move to individual vdevs? Or put all drives in a larger raid like Z2 or Z3?
Is there a recommended way to accomplish this? I can buy 2 more drives, should I just add 2 more and move everything? Make a new Pool altogether? I’m open to advice. 
If you lose a drive, the larger the disks and the more disks in the vDev, the longer the resilvering takes and the greater the risk that the stress of resilvering will cause a second drive to fail.
What everyone needs to remember is that ZFS RAIDZ is NOT like old-style single drives. With old style drives, if you lost a drive you lost only the data on that drive. With ZFS, if you lose a vDev you lose the entire pool of data. So you need greater redundancy.
My advice would be to start with a 6x RAIDZ2 and hope that the ZFS expansion capability will have arrived and be stable by the time you need to expand past 32TB of useable space.
Alternatively (which would be my recommendation) buy the extra 2x 8TB drives now and create an 8x RAIDZ2 from the off.
2 Likes
You can probably loose the cache (L2ARC?) drive. Usually added when RAM over 32-64GB and your ARC hit ratio is low. L2ARC usage eats into RAM a bit and just by installing it, you are lowering the memory available to ARC.
Please post a detailed hardware list as we use that info to make recommendations. If you post often, post it in your profile signature and you won’t have to repeat the info. Expand my sig or Protopia for an idea of what is posted
