Hello All: Had an issue after upgrading to the latest CentOS kernel from kernel-2.6.18-164.11.1.el5 to kernel-2.6.18-164.15.1.el5 on an IBM HS21 blade with SAN boot. Upgrade went fine, but after rebooting the system was unable to find /boot even though it was mounted. The reboot displayed an error with fsck.ext3 that /dev/mapper/mpath0p1 was not found, which was the /boot volume. I reverted to the old kernel and it booted fine.
At first I tried rebuilding the initrd to include the multipath modules, but this had no effect.
I ended up just re-labeling all the ext3 filesystems and the changing the /boot line in fstab from the /dev/mapper/mpath0p1 device to LABEL=/boot. This resolved the issue.
Any idea why the latest kernel did not see the /boot volume when specified as /dev/mapper/mpath0p1?