Hey,
I've got 4x400gb SATA drives and on each of them 4 partitions like this:
/dev/sdx1 - 128mb for RAID1 - /dev/md0
/dev/sdx2 - 1gb for SWAP
/dev/sdx3 - 40gb for / (RAID5) - /dev/md1
/dev/sdx4 - the rest for /extra (RAID5) - /dev/md2

Yesterday there was power failture and machine was restarted. Arrays
/dev/md0 and /dev/md1 were successfully resynced and are working OK,
however /dev/md2 array apparently cannot even be started.

I'm getting the following from mdadm:

[root@server:~]# mdadm --assemble --force /dev/md2 /dev/sda4 /dev/sdb4
/dev/sdc4 /dev/sdd4
mdadm: failed to RUN_ARRAY /dev/md2: Input/output error

[root@server:~]# dmesg
md: md2 stopped.
md: bind<sdb4>
md: bind<sdc4>
md: bind<sdd4>
md: bind<sda4>
md: kicking non-fresh sdd4 from array!
md: unbind<sdd4>
md: export_rdev(sdd4)
md: md2: raid array is not clean -- starting background reconstruction
raid5: device sda4 operational as raid disk 0
raid5: device sdc4 operational as raid disk 2
raid5: device sdb4 operational as raid disk 1
raid5: cannot start dirty degraded array for md2
RAID5 conf printout:
--- rd:4 wd:3 fd:1
disk 0, o:1, dev:sda4
disk 1, o:1, dev:sdb4
disk 2, o:1, dev:sdc4
raid5: failed to run raid set md2
md: pers->run() failed ...


Why is /dev/sdd4 suddenly marked as non-fresh? Is it possible to
rebuild/recover this array at all? None of the hard drives crashed and
are working OK.

--
Miha

Miha Verlic wrote:
> Why is /dev/sdd4 suddenly marked as non-fresh? Is it possible to
> rebuild/recover this array at all? None of the hard drives crashed and
> are working OK.

Hm that's odd:

[root@server:~]# mdadm -E /dev/sda4 | grep Events
Events : 0.1895249
[root@server:~]# mdadm -E /dev/sdb4 | grep Events
Events : 0.1895249
[root@server:~]# mdadm -E /dev/sdc4 | grep Events
Events : 0.1895249
[root@server:~]# mdadm -E /dev/sdd4 | grep Events
Events : 0.1895231

Does anyone have any clue why Events number on /dev/sdd4 differs? And
shouldn't RAID5 array start with only 3 drives, even though in ditry mode?
--
Miha