[Techtalk] software raid conundrum

kclair kclair at gmail.com
Wed Oct 13 13:32:58 EST 2004

Hi All,

i have been trying to help someone fix their server who is using linux
software raid.  I've never dealt with raid before.  I've read the
linux software raid how-to, but I still don't have a clear picture of
what I need to do to fix the situation, which is:

the software raid-1 was set up accessing two disk devices directly:
        device          /dev/hdc
        raid-disk       0
        device          /dev/hdb
        raid-disk       1

this started causing problems when the mirror started trying to write
to portions of the disks which should be inaccessible.  so, the plan
was to remove the devices, one at a time, from the array and then to
partition them and then readd them.  however, the devices are slightly
different sizes, and i didn't check which was which before starting,
so i ended up removing, partitioning, and readding the larger of the
two devices first.  after it had been readded and resynced, i removed
the second device.  of course, now i cannot readd that device because
the size of the array has grown to the size of the larger disk!

i'm a bit confused about how to proceed.  do i need to disassemble the
array and sync the disks somehow and then reassemble the array?  or
can i disassemble the array and then reassemble it and the raid
software will sync the disks, based on the data on the larger disk?

any advice is much appreciated.


More information about the Techtalk mailing list