Mailinglist Archive: opensuse (911 mails)

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Re: [opensuse] strange mdraid problem
07.12.2015 20:52, Istvan Gabor пишет:
Andrei Borzenkovírta:
07.12.2015 19:58, Istvan Gabor пишет:
Hello:

For some reason (probably a loose cable) all of my mdraid type 1
(mirror) arrays became degraded. After replugging the cables I
have resynchronized most of the arrays but not all of them. The
arrays that have been resynched work nicely but those devices
which I haven't resynched act strange: at every boot either one
or the other disk of the array is assembled to the array. That
is, one time /dev/md8 has /dev/sda8 assembled and /dev/sdb8
kicked off and the other time /dev/md8 has /dev/sdb8 assembled
and /dev/sda8 kicked off. By the time I discovered this I've had
different data on the two disks of the array.

My questions:

1. If an array becomes degraded and only one device is assembled
to it, the other one should be kicked off consequently after
this, until the array has been resynched or the missing deviced
is readded manually. Why then one or the other device is
assembled to the array at each boot?



Thanks, Andrei.

If only one piece is visible, how can mdraid know it is stale?

OK. How do I know that only one device is visible? I have several

I think similar topic was discussed relatively recently, may be even by you.

What version of openSUSE do you have? IIRC in 13.1 (and surely before)
one of startup scripts forcibly started degraded array; so if there was
any delay in discovering devices this could result in described behavior.

arrays and both devices are visible and assembled in the resynched
group. What you're saying is that in case of ~10 arrays (all have
been resynched after the failure) both devices are always visible
(dev/sda* and /dev/sdb*) but in case of not synched (and only in not
synched) either /dev/sda* or /dev/sdb* is visible alternatively at
different boots. How can I confirm that this causes the problem?


I would start with kernel logs, it could show relative timing of events.

2. How can I force mdraid to assemble only the same one of the
devices to the degraded array? (For example /dev/sda8 to /dev/md8
and not /dev/sdb8.)


Only by wiping out the wrong one.

You mean wiping out the raid info block (raid sector)?

Thanks,

Istvan


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