Mount an ext3 filesystem on linux so files on the mount are owned by a userid

According to a paper by Mathur et al. (p. 29), e2fsck time grows linearly with the amount of inodes on a filesystem after a certain point. If the graph is anything to go by, you're more effective with filesystems of up to 10 million inodes.

Switching to ext4 would help - under the condition that your filesystem is not loaded to the brim, where the performance gain (due to not checking inodes marked unused) has no discernable effect.

I once ran into a similar problem. In our case, someone created a partition to hold the PV, but when they ran the pvcreate command, they forgot to specify the partition and instead used the whole device. The system ran fine until a reboot, when LVM could no longer find the PV.

So in your case, is it possible that someone ran "pvcreate /dev/mapper/mpath0" at the time of creation rather than "pvcreate /dev/mapper/mpath0-part1"? If so, you'll need to remove the partition table from the disk containing the PV.

From the pvcreate(8) man page to delete a partition table:

dd if=/dev/zero of=PhysicalVolume bs=512 count=1

The LVM code in the kernel will not recognize a whole device PV if there is a partition table on the device. Once we removed the partition table, the PV was recognized and we could access our data again.