[Linux-PowerEdge] RAID-1 with inconsistent parity data?

Stefan M. Radman smr at kmi.com
Sat Mar 8 15:31:05 CST 2014


I followed the very helpful article on double faults and punctures referred to by Josh Moore a while ago (thanks Josh)

http://www.dell.com/support/troubleshooting/us/en/19/KCS/KcsArticles/ArticleView?c=us&l=en&s=dhs&docid=438291
and used the OMSA CLI to start a consistency check on my two virtual disks

# omconfig storage vdisk action=checkconsistency controller=0 vdisk=0
# omconfig storage vdisk action=checkconsistency controller=0 vdisk=1

The check on vdisk1 (RAID-5) is still running but for vdisk0 (RAID-1) I received several error messages all reading:

OMSM : The Check Consistency found inconsistent parity data. Data redundancy may be lost.:  Virtual Disk 0 (PERC H700 Integrated) Controller 0 (PERC H700 Integrated)

A little bit later the consistency check completed (Result=Passed) with

The Check Consistency made corrections and completed.: Virtual Disk 0 (PERC H700 Integrated) Controller 0 (PERC H700 Integrated)

Is this something I should worry about considering the fact that RAID-1 does not have parity?
Still wondering what was corrected…

Stefan

Am 12.02.2014 um 04:43 schrieb Josh_Moore at Dell.com<mailto:Josh_Moore at Dell.com>:


Dell Customer Communication
What the agent is referring to is known as a punctured array
You can see more detail regarding double faults and punctures in the following Dell article
http://www.dell.com/support/troubleshooting/us/en/19/KCS/KcsArticles/ArticleView?c=us&l=en&s=dhs&docid=438291
Note, that punctures are a feature of Dell PERC controllers, and other LSI based controllers, and allows for impacted arrays to rebuild with errors, where those errors might have otherwise prevented the array from rebuilding at all or worse.
Rebuilding a replacement for a failed drive, while another drive in the array is at issue can result in puncturing the array
Leaving an array punctured however can lead to other faults, and as such when multiple drives within an array are impacted (failed, or predicting failure) we recommend a backup, recreating the array and reinstall/restore.

-----Original Message-----
From: linux-poweredge-bounces-Lists On Behalf Of John G. Heim
Sent: Tuesday, February 11, 2014 8:57 PM
To: David Brůha; Steve Thompson
Cc: linux-poweredge-Lists
Subject: Re: [Linux-PowerEdge] raid5 vs raid6

Here's a segment of a chat between my co-worker and Dell tech support.
They are  recommending that we re-install because of "legacy corruption". I googled "legacy corruption" but I can't find anything that makes sense.

--- begin transcript ---
Dell: Ok, for this type of "double failure", we would recommend replacing both hard drives and creating a new virtual disk.

You would then restore the data to this new virtual disk.

Customer : it's not a situation where we could replace one and get the info to replicate and then replace the other?

Dell: No, because the virtual disk would have legacy corruption affecting it.
--- end transcript ---

What gives?



On 02/11/2014 07:22 PM, David Brůha wrote:
> Dne středa 12 Únor 2014 02:00:23 Steve Thompson napsal(a):
>> On Wed, 12 Feb 2014, David Brůha wrote:
>>> I admint I don't know if you can convert your RAID-5 to RAID-6 - I
>>> would say probably not without copying data elsewhere. However
>>> RAID-6 in your 4 disk environment would mean 2 drive failure tolerancy.
>> Yes, you can convert RAID-5 to RAID-6 on a Perc 6+; done it several times.
>>
>> Steve
>>
> Nice to know, thank you, didn't know that.
>
> David
>
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> Linux-PowerEdge at dell.com<mailto:Linux-PowerEdge at dell.com>
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