If you, like me, love LVM for your Linux installations and LVM's ability to add disk space to partitions before they fill up without reboot or unmounting... then you'll be glad to know you can also use LVM if you have EMC PowerPath for your multi-path issues.
In a bug fix from 2005, rhn.redhat.com | Red Hat Support, Red Hat lists that you can use Powerpath pseudo-devices with LVM. That way, LVM is unaware of a path failure and will get the fail-over path from PowerPath.
Update: What you should do, though, is tell LVM to ignore local devices and only focus on emcpower devices. I distinguish between VMs and bare metal (BM) servers that also have local SAS disks. Here is what I've put in the lvm.conf file:
# add EMCpower devices and sdb, reject all other SCSI disks and any CDs
#BM#filter = [ "a|/dev/emcpower.*|","a|/dev/sdb|","r|/dev/sd.*|","r|/dev/cd.*|" ]
# add any SCSI devices, reject all IDE disks and CDs
#VM#filter = [ "a|/dev/sd.*|","r|/dev/hd.*|","r|/dev/cd.*|" ]