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

- From: Adam Thompson \<hidden\>
- Date: 2015-02-11 03:37:36 
- List: linux-raid
- Page: https://ratatoskr.run/linux-raid/2015/02/6628969
- Thread: https://ratatoskr.run/linux-raid/2015/02/6628969/t.md

```text
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
 athompso@athompso.net
 +1 (204) 291-7950 - cell
 +1 (204) 489-6515 - fax

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