Re: Raid-6 cannot reshape

[Phil Turmel <philip@turmel.org>]

Hi Allie,

On 4/7/20 6:25 AM, Alexander Shenkin wrote:
> 
> 
> On 4/6/2020 9:34 PM, Phil Turmel wrote:
>> On 4/6/20 12:27 PM, Wols Lists wrote:
>>> On 06/04/20 17:12, Roger Heflin wrote:
>>>> When I looked at your detailed files you sent a few days ago, all of
>>>> the reshapes (on all disks) indicated that they were at position 0, so
>>>> it kind of appears that the reshape never actually started at all and
>>>> hung immediately which is probably why it cannot find the critical
>>>> section, it hung prior to that getting done.   Not entirely sure how
>>>> to undo a reshape that failed like this.
>>>
>>> This seems quite common. Search the archives - it's probably something
>>> like --assemble --revert-reshape.
>>
>> Ah, yes.  I recall cases where mdmon wouldn't start or wouldn't open the
>> array to start moving the stripes, so the kernel wouldn't advance.
>> SystemD was one of the culprits, I believe, back then.
> 
> Thanks all.
> 
> So, is the following safe to run, and a good idea to try?
> 
> mdadm --assemble --update=revert-reshape /dev/md127 /dev/sd[a-g]3

Yes.

> And if that doesn't work, add a force? >
> mdadm --assemble --force --update=revert-reshape /dev/md127 /dev/sd[a-g]3

Yes.

> And adding --invalid-backup if it complains about backup files?

Yes.

> Thanks,
> Allie

Phil