Isto é o que eu tenho usado para sistemas com dm-multipath e LVM; modificar conforme necessário:
1) Increase size of LUN in SAN 2) Check with "multipath -ll" which devices belong to said LUN 3) For each device above, do "echo 1 > /sys/block/sdX/device/rescan" 4) Go to multipath command line with "multipathd -k" 5) For each device, do "del path sdX", "add path sdX" while hoping that the multipathing functionality works as advertised and fails over properly. 6) "resize map multipath-map-name" 7) Exit multipath command line (Ctrl-D), check with "multipath -ll" that new size is seen. 8) pvresize, lvextend, resize2fs 9) Profit!
Isso funciona como no RHEL 5.3.