ZFS Raidz3 5 Drives?

I am making a simple san for my office. We have some mission critical information we cannot lose. My understanding is that in a Raidz3 we can lose up to two drives without losing the data. I intend on using 5 2TB Western Digital Red Drives. Am I wrong in any of this understanding or can I achieve triple parity with 5 drives with something else. Whats important above anything is data integrity. Not speed or size.

If data integrity is king why complicate things with raid? Just use mirrored drives and several detachable backups. I think your backup policy and hardware config (ecc, redundant PSU, ups, monitoring software) will be more effective in keeping data safe. Plus with normal jbod, data recovery will be a breeze.

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With RAIDZ2 you can lose 2 drives and still be working.

But yeah, mirrors are real nice for this. Rebuild times are stupid fast and have very little impact on the CPU. Really the one downside is you do sacrifice a lot of space. But as drive sizes expand and prices come down, space becomes less of a hurdle.

So would you recommend a mirror raidz2 config?

I tend to go mirrors unless there are other wants and needs. If it’s just data integrity, it’s hard to beat mirrors.

If you’ve got other limitations like total number of harddrives possible in the machine, or budget constraining the size of the drives (mirrors eat up a lot of space), or something like that, then yeah, RAIDZ2.

I am using 5x4TB drives in RaidZ2 with FreeNas. I can lose two drives and still have all of my data. It is possible but it might not be optimal, I’m not an expert.

Lots more info here: