Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm building a RAIDZ2 ZFS system, using Ubuntu 13.10 as a base system, and zfsonlinux's packages, having 6 disks dedicated to the pool data and a couple of SSD partitions to do ZIL log and L2ARC cache. My HDDs are all 2.0TB (ie: slightly less than 2.0 TiB) drives.

Yet, once the pool was created, zpool list unexpectedly reports a pool having 10.9T size, 1.93M allocated, and 10.9T free. How is it getting nearly 11T free in a RAIDZ2 having a total of 12.0 of disks? I was expecting to have a mere 8.0T of free space.

Oh, this is apparently a very similar question to ZRAID1 pool size bigger than expected, but about RAIDZ2 instead of RAIDZ... I'll post this anyway, in case anyone cares about RAIDZ2 for their searches.

share|improve this question

It turns out that each drive is 1.82TiB. That, times 6 = 10.9TiB. I suppose zpool reports the total physical space available for filesystem labour (ie: data + parity) as opposed to just the space available for user data without the parity factored in.

In fact, the "duplicate question" has a perfectly good answer already, quoted here (added dashes for clarity):

zpool list - shows the size of the pool, which is the size of all the disks.

zfs list - shows the usable file systems sizes in the pool.

PS. Maybe we should have a "raidz2" tag.

share|improve this answer
(don't use raidz or raidz2!!) – ewwhite Dec 31 '13 at 18:31
Because: - There are serious compromises to using RAIDZ(1,2,3) in your ZFS arrays. Performance, expandability, complexity... – ewwhite Dec 31 '13 at 19:19

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.