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I have never put together a RAID array before, but i think i understand the concepts behind most raid types from my reading.

Ordering three 3TB drives (WD red) to use in a xeon e3-1231 v3, 16GB non-ECC RAM and Z97 chipset. I have other systems available via SSH on local net, but with much less (~1TB) space.

My OS (Debian Linux) is on a SSD, the raid will not contain an OS.

I came across ZFS recently and might be failing to fully understand its desired implementation.

Compared to a hardware RAID 5 on intel z97 chipset..

  • Would using ZFS increase performance?
  • Would it be a safer option for my data with equal parity?
  • Would rebuild be safer and faster if a drive suddenly fails?
  • What if my SSD fails? isnt ZFS data saved there in my case?

I need my data to be safe (hopefully every block, which is why ZFS interests me), and at least 6TB of usable space without needing more HDDs.

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  • The Intel z97 doesn't do RAID5 in hardware. It's still software RAID, aka fakeraid.
    – ChrisInEdmonton
    May 18, 2015 at 8:30
  • I came across someone else saying that as well, i will be doing even more reading into ZFS, it might be the best option given the lack of dedicated hardware controller (even though it looks like a hardware raid, it seems it isn't one).
    – user2225483
    May 18, 2015 at 13:16

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  • Would using ZFS increase performance?

Hard to say without knowing your typical disk usage and how you configure your system. For example, how much RAM will you allow ZFS to use? The parity calculations between RAID-Z1 and RAID 5 would probably have similar overheads.

  • Would it be a safer option for my data with equal parity?

If you mean a mirror, then yes. Mirrors take less time to rebuild (no parity) so your data would be at risk for a shorter duration.

  • Would rebuild be safer and faster if a drive suddenly fails?

For a mirror, yes. For RAID-Z1 and RAID 5, rebuild requires parity calculations so rebuilds will take longer.

  • What if my SSD fails? isnt ZFS data saved there in my case?

ZFS pools are self-contained and can run independently of any settings on you SSD. You can even move your ZFS drives to a completely different OS, providing it supports the ZFS version. (I have successfully moved a 3 drive RAID-Z1 pool from OpenSolaris to FreeBSD.)

Other comments:

ZFS offers more than redundancy. It has other features that RAID 5 does not, such as checksums throughout the filesystems to ensure data integrity and snapshots.

ZFS loves memory and will use as much as you care to give it. ECC memory is recommended but not required.

I use ZFS for personal use. I used to run RAID-Z on three drives but now run four drives as a striped mirror and am much happier with the performance. Scrubbing times have been greatly reduced which means that a rebuild should also be faster. Of course, the trade off is reduced usable capacity.

Regardless of what type of redundancy you choose, make sure you acquaint yourself of the options (and limitations) you have if you want to upgrade the capacity in future.

And finally...

Backup. Backup. Backup.

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  • could you elaborate on differences of free space in the ZFS method?
    – user2225483
    May 18, 2015 at 13:18
  • @user2225483, you've already asked 4 questions here. I suggest you start a new question (if it hasn't already been asked on this site) and elaborate a bit further what you mean by "differences of free space."
    – Mike Fitzpatrick
    May 18, 2015 at 23:05

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