The release notes of Suse Linux Enterprise 10 state that the root partition on multipath is only supported if the /boot partition is on a separate non-multipathed partition else no bootloader will be written.

 It took me four days of faultfinding to notice this in the release notes.

 The fix is very easy; Apply the updates.

There are a few more steps to fix the degraded mirror;

1) Open Expert Partitioner by typing

yast2 disk

at the command line. You will observe that mdx is shown against one of the mirrored partitions but not both.

 2) Expert Partitioner will not let you fix the degraded mirror, instead type

mdadm /dev/md0 --add /dev/sdb2

at the command line replacing md0 with the name of your mirror and replacing /dev/sdb2 with the name of the partition missing the mdx shown in Expert Partitioner. Nb There are two dashes before add in the above command.

3) Now click on the expert button in Expert partitioner and choose to Reread the partition table. You will now find that both partitions show that they are mirrored.

In fact if you use the mdadm -D /dev/md0 command as shown in the top screencapture you will see that the mirror is being rebuilt.

Hot spare

 A better solution may be to create a hot spare. We can set up three hard drives as members of a RAID 1 array with one being a spare. The spare does not have anything written to it. If one of the other two drives in the mirror set fails then the spare will automatically replace the failed unit and be automatically mrrored.

E g We create two mirrors on three SATA hard drives.

# Build the first mirror with the / partition by issuing the following commands after creating identical partitions on each of three SATA hard drives usi