Re: Linux software raid troubles

[Reindl Harald <h.reindl@thelounge.net>]

Am 12.04.2017 um 16:31 schrieb linuxknight:
> Last weekend I was moving a server with a raid1 configuration,
> controlled by a Intel Corporation 82801 SATA RAID Controller.  Upon
> reboot I noticed the degraded message (server hadnt been rebooted in a
> couple years).
> 
> The raid1 array was two 500gb black WD drives.  I wasnt able to locate
> an identical 500gb disk, but did find a 2TB just to get things
> mirrored again.  The bios screen accepted the replacement disk and
> said it would rebuild in the OS.  mdsync seemed to do its thing but I
> noticed mdmon process was taking 200% cpu.  I let it go a few days
> thinking it was just taking longer than normal to sync, then rebooted.
> It was in a complete failed state and wouldnt boot at all.  After
> removing the 2TB disk I was able to boot into the OS again.  I just
> assumed I needed a similar drive size for the second part of the
> mirror.

when you talk about a "SATA RAID Controller" and "The bios screen 
accepted the replacement disk and said it would rebuild in the OS" this 
sadly is not a "linux software raid" at it's own

197 Current_Pending_Sector  -O--CK   200   200   000    -    9
198 Offline_Uncorrectable   ----CK   200   200   000    -    7

i would strongly suggest https://www.gnu.org/software/ddrescue/ and make 
a image of that disk because after 39646 Power_On_Hours it's likely that 
the remaining disk fails completly in a short time and you could at 
least restore the disk-image with "dd" to a new disk if that happens as 
well as mount it with as loop-device