On Sun, 2015-01-11 at 00:13 +1100, Daniel Hoffman wrote:
Hi All.
Looking for some guidance/experience with LVM and pvmove.
I have a LUN/PV being presented from a iscsi SAN. The LUN/PV is presented to 5 servers as a shared VG they all have LV's they use for data, they are all connected via iSCSI.
As the SAN I am using is being replaced I need to move onto a new unit.
My migration strategy at this time is to
- Present a new LUN from the new SAN to all machines.
- Make a PV with the new LUN.
- Add it to the existing VG.
- Use pvmove to move all the data from one PV to another.
- Once the old LUN is empty, complete a pvresize to remove the old LUN.
This all seems sound but looking for advice, specifically around the fact that the VG/PV data is being used by a number of machines/servers and the LV's are active on a number of different nodes.
All the documentation/examples I can find assume a disk in a server, not a LUN on a SAN being shared by a number of servers.
Any advice is appreciated.
Cannot help with the SAN question other than to say that you are just adding another PV block device to a VG and LVM shouldn't care.
My comment is on step 5. You want to "vgreduce -a <VG>" to remove empty PVs (assuming only the old one is empty) followed by "pvremove <PV>" to remove the old PV.
As always, be wary of any "Are you sure?" or "You need to --force" LVM output.
Steve