Re: [Board] dead RAID6 array on CentOS6.6 / kernel 3.19

Re: [Board] dead RAID6 array on CentOS6.6 / kernel 3.19

[Adam Thompson]

On 2015-02-10 08:58 PM, Trevor Cordes wrote:
> The big first question is was it lying when it said starting bg recon. 
> Probably. How can it rebuild a 3+ drive failure.
>
> If so it should be possible to really force. As in wild wacky stuff. 
> I've done that before.
>
> I can look at it more after the meeting our tomorrow morning.
>
> Was the reboot a clean or a sysreq? Did it sync first?

Manually initiated by reboot(8), which is a link to telinit(8), which 
merely sends a signal to init(8), which actually did the reboot.
No idea if /dev/md127 correctly stopped or not, syslogd stops before 
those messages get logged, and I was working remotely through SSH 
instead of to the virtual console connection.
I would assume the sync(2) happened correctly; this is breakage way down 
at the MD layer, not the FS layer.

You're right, RAID6 can't rebuild from a 3-drive failure.  I've gone 
back through the messages I sent, and it looks like there was no 
hot-spare, so I suspect this is just the default code path, where it 
tries to rebuild anything it can, then figures out it can't.


-- 
-Adam Thompson
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