welcome AGnett,


are these ASM devices or you are using regular LVM ? How are you planning on migrating the data (cpio , rsync ... ? ). What type of array is it on ?

LVM
RAID 5
Migation (not sure)

i've never tried this on Linux but seems like "lvconvert" could do the job. A simpler solution would be present new smaller devices, build new volume group/logical volume. Shutdown Oracle, cpio data files from old logical volume to new logical volume. Unmount old and new logical volumes and remount new logical volumes under the old mount point names. Also don't forget to fix /etc/fstab to point to new volume group/ logical volumes.

I would try pvmove. See section 13.5.2

http://www.linux.org/docs/ldp/howto/LVM-HOWTO/removeadisk.html

Pvmove is a valid strategy, but remember to MAKE SURE YOUR BACKUPS ARE GOOD before starting a pvmove-style migration. If something unexpected happens while pvmove is running (like power going out, or someone tripping over the storage cables) it is possible that your VG will fail to come back up... in which case re-creating the VG from scratch and restoring the data from backups will very probably be the quickest way to get the system back to normal.

Of course, having a pvmove running will eat a big slice of your disk I/O capacity, so you will want to do that at a time when your system is otherwise as idle as possible.

pvmove is design to modify physical volumes collection under the existing logical volume. If you google this command, you will find enough evidence that even without power outage and system failure, the procedure is NOT production ready.

So its up to you to chose.I wont take a chance in PROD