It is possible, but i would not recommend it. I have done it once.
One way to do it
Add your new iscsi storage
Create new PV on the new storage and expand your current VG to the new volume
Move some or all machines from your old storage with "pvmove"
There is the following problems (and maybe more)
If somethings goes wrong - lost connection, iscsi server crash etc, your filesystem will possibly be damaged beyound repair (my was)
If you have a cluster werid things would happen if you do not do some kind of work on the all machines (maybe some refresh etc). (no CLVM om 1.9)
I did it, but in the end i needed to recover one machine from backup, and needed to reboot the whole cluster - i would not do it again without clvm (and backups off cause).
Best Regards
