Looking for raidz arrangement advice

[bassmannate]

First time set up of TrueNAS Scale here. I have 8ea 3TB drives and my initial plan was go with raidz3 hoping for ~15TB of storage. However, I didn't think about the overhead loss so each drive is actually reporting as 2.73TB meaning my pool would only be 13.64TB. That's still a whole lot of network storage for me.

I did plan ahead and got 2 extra identical drives sitting in a drawer as spares to swap in. Would I be better off with this many drives of this size going with raidz2? It's what TrueNAS is defaulting to when I add all the drives into the pool so maybe the OS knows better than me?

 

[Arwen]

If you have cold, (but burn in tested), spare disk drives, RAID-Z2 with 8 drives is a reasonable configuration. (RAID anything is not a backup, so you should have a backup as well.)

RAID-Z3 is a bit super safe, but is a little bit slower. And obviously takes 1 more disk's worth of storage for the third parity. Unless you have specific requirements, like being away from the server for weeks at a time, or need higher reliability, RAID-Z2 should be "good enough".

 

[bassmannate]

If you have cold, (but burn in tested), spare disk drives, RAID-Z2 with 8 drives is a reasonable configuration. (RAID anything is not a backup, so you should have a backup as well.)

RAID-Z3 is a bit super safe, but is a little bit slower. And obviously takes 1 more disk's worth of storage for the third parity. Unless you have specific requirements, like being away from the server for weeks at a time, or need higher reliability, RAID-Z2 should be "good enough".

This makes sense. I do have 2 cold drives in reserve at the moment and I've talked to my father to do some back up exchange as he has a NAS 700 miles away. This should kill 2 birds with one stone and give us both geographically isolated offsite backup.

Raidz2 it is then!