I have a software RAID-1 setup up on two identical sata drives
using the promise-sata driver. It appears that the sda drive of
this RAID-1 combination has developed bad media. The problem
arose when the machine wouldn't reboot into grub after a shutdown.
I finally managed to get the raid-1 to reboot for sda (but all the
sdb devices were deattached from the raid). After doing a
raidaddhot on each sdb device for its matching md device, I
saw the raid-1 resyncing each md device. However when it got to
the /home partition on /dev/sda6 it seemed to run into media errors...
Current sda: sense key Medium Error
Additional sense: unrecovered read error - auto realllocate failed.
Repeated attempts at rebooting and resyncing gave the same result.
I also found that when I attempted to back data off of /dev/sda6
onto a remote machine that the copy hung (apparently due to bad
blocks).
I decided to try the second drive of the mirror instead
by detaching the master sata drive. The problem I ran into was that
when accessed as a /dev/md4 device the mounting always failed
due to a bad superblock error which e2fsck couldn't repair. However
if I edited /etc/fstab to change from /dev/md4 to /dev/sda6 then
the /home partition could be mounted.
Thus the problem as I understand it is that my master raid-1 drive
(which normally is sda) has bad media. The slave raid-1 drive has the
md4 device mangled due to an incomplete resync (since the /dev/sda6
partition has bad media in it). With the master raid-1 sata drive
detached I am able to boot the raid-1 but only if I use /dev/sda6
for /home rather than /dev/md4 in /etc/fstab.
The problem I now have seems to be...
How do I convince the raid-1 for /dev/md4 that the superblock on
/dev/sda6 is really okay so that it can be mounted as /dev/md4 again?
I would like to leave the master sata drive deattached for now but
be able to mount all the raid-1 partitions from the second raid-1 drive
(which will be sda). If I can do that I intend to replace the master sata
drive, repartition it identically to the second drive and attempt to
resync the partitions off of sdb (which will the slave sata will be
again if I reboot with a clean drive attached to the master sata
drive port). Thanks in advance for any advice on this.
Jack
