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Some additional points for posterity, in case it isn't driven home here: - All redundancy in ZFS is built in the vdev layer. Zpools are created with one or mor

Some additional points for posterity, in case it isn't driven home here: - All redundancy in ZFS is built in the vdev layer. Zpools are created with one or more vdevs, and no matter what, if you lose any single vdev in a zpool, the zpool is permanently destroyed. - Historically RAIDZs (parity RAIDs) cannot be expanded by adding disks. The only way to grow a RAIDZ is to replace each disk in the array one at a time with a larger disk (and hope no disks fail during the rebuild). So in my very amateur opinion, I would only consider doing a RAIDZ if it is something like a RAIDZ2 or 3 with a large number of disks. For n<=6 and if the budget can stand it, I would do several mirrored vdevs. (Again as an amateur I am less familiar with RW performance metrics of various RAIDs so do more research for prod).

sgarland 3y ago
Pool of mirrors is usually the safer way, yes. If and only if you a. Have full, on-site backups b. Are fairly sure of your abilities and monitoring then I can suggest RAIDZ1. I have a pool of 3x3 drives, which ships its snapshots a few U down in my rack to the backup target that wakes up daily, and has a pool of 3x4 drives, also in RAIDZ1. In the event that I suffer a drive failure in my NAS, my plan of action would be to immediately start up the backup, ingest snapshots, and then replace the drive. That should minimize the chance of a 2nd drive failure during resilvering destroying my data. Truly important data, of course, has off-site as well.