[CentOS] C7, mdadm issues

[mark]

On 01/30/19 03:45, Alessandro Baggi wrote:
> Il 29/01/19 20:42, mark ha scritto:
>> Alessandro Baggi wrote:
>>> Il 29/01/19 18:47, mark ha scritto:
>>>> Alessandro Baggi wrote:
>>>>> Il 29/01/19 15:03, mark ha scritto:
>>>>>
>>>>>> I've no idea what happened, but the box I was working on last week
>>>>>> has a *second* bad drive. Actually, I'm starting to wonder about
>>>>>> that particulare hot-swap bay.
>>>>>>
>>>>>> Anyway, mdadm --detail shows /dev/sdb1 remove. I've added
>>>>>> /dev/sdi1...
>>>>>> but see both /dev/sdh1 and /dev/sdi1 as spare, and have yet to find
>>>>>> a reliable way to make either one active.
>>>>>>
>>>>>> Actually, I would have expected the linux RAID to replace a failed
>>>>>> one with a spare....
>>
>>>>> can you report your raid configuration like raid level and raid devices
>>>>> and the current status from /proc/mdstat?
>>>>>
>>>> Well, nope. I got to the point of rebooting the system (xfs had the
>>>> RAID
>>>> volume, and wouldn't let go; I also commented out the RAID volume.
>>>>
>>>> It's RAID 5, /dev/sdb *also* appears to have died. If I do
>>>> mdadm --assemble --force -v /dev/md0  /dev/sd[cefgdh]1 mdadm: looking for
>>>> devices for /dev/md0 mdadm: /dev/sdc1 is identified as a member of
>>>> /dev/md0, slot 0.
>>>> mdadm: /dev/sdd1 is identified as a member of /dev/md0, slot -1.
>>>> mdadm: /dev/sde1 is identified as a member of /dev/md0, slot 2.
>>>> mdadm: /dev/sdf1 is identified as a member of /dev/md0, slot 3.
>>>> mdadm: /dev/sdg1 is identified as a member of /dev/md0, slot 4.
>>>> mdadm: /dev/sdh1 is identified as a member of /dev/md0, slot -1.
>>>> mdadm: no uptodate device for slot 1 of /dev/md0
>>>> mdadm: added /dev/sde1 to /dev/md0 as 2
>>>> mdadm: added /dev/sdf1 to /dev/md0 as 3
>>>> mdadm: added /dev/sdg1 to /dev/md0 as 4
>>>> mdadm: no uptodate device for slot 5 of /dev/md0
>>>> mdadm: added /dev/sdd1 to /dev/md0 as -1
>>>> mdadm: added /dev/sdh1 to /dev/md0 as -1
>>>> mdadm: added /dev/sdc1 to /dev/md0 as 0
>>>> mdadm: /dev/md0 assembled from 4 drives and 2 spares - not enough to
>>>> start the array.
>>>>
>>>> --examine shows me /dev/sdd1 and /dev/sdh1, but that both are spares.
>>> Hi Mark,
>>> please post the result from
>>>
>>> cat /sys/block/md0/md/sync_action
>>
>> There is none. There is no /dev/md0. mdadm refusees, saying that it's lost
>> too many drives.
>>
>>        mark
>>
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> 
> 
> I suppose that your config is 5 drive and 1 spare with 1 drive failed.
> It's strange that your spare was not used for resync.
> Then you added a new drive but it does not start because it marks the new disk 
> as spare and you have a raid5 with 4 devices and 2 spares.
> 
> First I hope that you have a backup for all your data and don't run some 
> exotic command before backupping your data. If you can't backup your data, 
> it's a problem.

This is at work. We have automated nightly backups, and I do offline backups 
of the backups every two weeks.
> 
> Have you tried to remove the last added device sdi1 and restart the raid and 
> force to start a resync?

The thing is, it had one? two? spares when /dev/sdb1 started dying, and it 
didn't use them.
> 
> Have you tried to remove this 2 devices and re-add only the device that will 
> be usefull for resync?  Maybe you can set 5 devices for your raid and not 6, 
> if it works (after resync) you can add your spare device growing your raid set.

I tried, and that's when I lost it (again), and it refuses to assemble/start 
the RAID "not enough devices".
> 
> Reading on google many users use --zero-superblock before re-add the device.

I can take one out, and re-add, but I think I'm going to have to recreate the 
RAID again, and again restore from backup.
> 
> Other user reassemble the raid using --assume-clean but I don't know what 
> effect it will produces
> 
> Hope that this helps.

Thanks.

	mark