Good afternoon everyone. I currently have TrueNAS Core with 4 x 4TB in a RAID Z2 configuration with regular snapshots. My current backups for the NAS are a 4TB external hard drive in our safe at home and another 4TB external hard drive in the safe at the bank. We back them up periodically and swap them out.
I’m ready now to build an offsite backup with an upgrade at the same time. I’m going to upgrade to Scale and both systems will end up with 8 x 4TB hard drives. For context, I use WD Red Plus drives.
My question is, is RAID Z1 appropriate for both of the systems or should they be RAID Z2?
IMO, raidz1 is good for backup. Regarding the main system – it’s a complicated/opinionated topic. I personally think that raidz1 is ok as long as you have backups.
Strictly speaking, raid(z) is for uptime, not for data loss protection (you should have backups for this).
In my opinion, the larger the drive, or the more drives per RAID-Z1 vDev, the less safe it is. Roughly, (and again just my opinion), something like this, for maximum:
8 x 1TB
5 x 2TB
3 x 3TB
Too large of a drive, especially these new ones that are 30TBs or close to it, is a risk with just 1 parity. Making a wide RAID-Z1, like 12 disks, is also to risky, (in my opinion). Doing both, (in my opinion), is a recipe for disaster.
