CentOS 5 Server :: ISCSI Volumes No Longer Mount After Reboot?

We have a Centos 5.6 server mounting two iSCSI volumes from an HP P2000 storage array. Multipathd is also running, and this has been working well for the few months we have been using it. The two volumes presented to the server were created in LVM, and worked without problem.We had a requirement to reboot the server, and now the iSCSI volumes will no longer mount. From what I can tell, the iSCSI connection is working ok, as I can see the correct sessions, and if I run 'fdisk -l' I can see the iSCSI block devices, but the O/S isn't seeing the filesystems. Any LVM command does not show the volumes at all, and 'vgchange -a y' only lists the local boot volume, not the iSCSI volumes. My concern is that, the output of 'fdisk -l' says 'Disk /dev/xxx doesn't contain a valid partition table' for all the iSCSI devices. Research shows that performing the vgchange -a y command should automatically mount any VG's that aren't showing, but it doesn't work.

There's a lot of data on these iSCSI volumes, and I'm no LVM expert. I've read that some have had problems where LVM starts before iSCSI and things get a bit messed up, but I don't know if this is the case here (I can't tell), but if there's a way of switching this round that might help, I'm prepared to give it a go.There was absolutely no indication there were any problems with these volumes, so corruption is highly unlikely.