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 trying to create a raid 6 array on a VNX 5100 from EMC, however am unable to create one with 7 drives. We have 8 total, and I immediately carved one out for hot sparing, leaving me 7 data drives. I can create one with 6 or 8, not 7. I am also unable to make a raid with 5 drives, which leads me to believe that odd numbers of disks are not eligible for raid 6. Raid 5 gives me no such issues.

Raid 6 should not have a dependency on having an even number of drives. Its only dependency should be meeting the minimum number of 4 drives. Can anyone help me find a way around this?

share|improve this question
Small nitpick: The minimum for RAID6 is three drives, not four, at least in the general (non-EMC?) case. – Sven Oct 24 '11 at 16:54
Not really- the standard cites a minimum of 4. Otherwise you'd just essentially have a 3 way mirror. – Basil Oct 24 '11 at 16:58
This is probably not what you want to hear, but.. this really sounds like a question for EMC technical support. It also sounds like it would probably cost less money if you just bought another drive. – user606723 Oct 24 '11 at 17:09
@user606723 Assuming there's space for another disk in the shelf. – MDMarra Oct 24 '11 at 18:00
We're going to have to buy another drive- that's annoying, but at least we have room in the shelf :) – Basil Oct 24 '11 at 19:29
up vote 3 down vote accepted

Here's an EMC PDF. Page 6 is what you are looking for.

share|improve this answer

EMC implements RAID6 using the EVENODD technique, which requires an even number of disks.

share|improve this answer
Get me a link to an EMC document to that effect and you've got the check :) Thanks! – Basil Oct 24 '11 at 19:04

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.