Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

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 have 8 hard drives of different sizes that I want in a RAID 5 or 6 configuration, the OS is Ubuntu 12.04 desktop.

Does the native RAID in Ubuntu support RAID configurations with hard drives of different sizes? Can i grow the RAID in the future?

If not, is ZFS a good alternative to this?

I have looked at other alternatives like FlexRAID (support is terrible and documentation is just as reliable), UnRAID, and snapRAID but there seems to be limitations with each of them. But, ZFS seems to be a good long term solution for RAID management and growth.

share|improve this question
I'm going to imagine these are cheap consumer 1/2/3TB SATA disks right? either way don't even CONSIDER R5 ok, please. – Chopper3 Feb 9 '13 at 15:39
Some are, yes. I have two 3tb WD RED drives. I am not in the market for SAS or SSDs. I need lots of storage and paying SAS prices are not an option. Any thoughts besides the quality of my HDs? – Erik Feb 10 '13 at 1:45
BTW, why are you opposed to RAID5? – Erik Feb 10 '13 at 1:57
@Erik The rebuild time of large-capacity disks in RAID 5 is a problem. See: What are the different widely used RAID levels and when should I consider them? – ewwhite Feb 10 '13 at 2:55
You should now that RAID-Z (aka RAID-5 on ZFS) can work perfectly even with 4TB consumer grade disk. Something that would not work on an enterprise RAID system. ZFS can build or rebuild only what is necessary or in other words has been used by files. However, if the disks would be near to full, then RAID-Z2 would be a must then esp on 4+TB disks. Because the rebuild of close to 4TB data is nearly sure to generate one disk read error, ZFS would detect it but unless there is a second redundant disk, there is little it can do to recover that file. – Huygens Feb 10 '13 at 16:57

Different sizes? Hmm...

Your software RAID can support drives of different sizes. As for ZFS, there are some caveats to understand before deployment. The main issue would be that RAIDZ volumes can't be expanded. ZFS mirrors are almost always a better option for growth. Also, there are some boot considerations when attempting to do this in Linux.

However, if you're concerned about a long-term solution, wouldn't it make sense to try to obtain like-sized disks?

share|improve this answer
I appreciate your feed back on ZFS. I've read other users' concerns about booting with ZFS, this is certaintly something to consider. To your question about hard drives, I agree with you that having homogeneous drives are desirable and that is my plan indeed; ill add them piece by piece but in the mean time i need the best solution that will see me through. – Erik Feb 10 '13 at 1:54
Go with mirrors if you can. At least that's an expandable solution versus RAIDZ. – ewwhite Feb 10 '13 at 1:55
Thank you again for your help – Erik Feb 10 '13 at 1:56

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.