A zillion reasons to use LVM in a Virtual Machine environment
So this question pops up on irc on how to manage disks for Xen Virtual domains ..
When I answer LVM people always wonder why .. afterall they only have one disk I often ask the following questions : How many partitions can you create on 1 disk ?
When not using LVM can you resize your paritions when you need them ? Do you often run into the
"The kernel still uses the old table. The new table will be used at the next reboot." issue when trying to add partitions ?
With LVM you don't have these problems , and those are only 3 of the LVM advantages that have nothing to do with striping, mirroring or snapshotting
Actually you just create partitions (/var/ /usr/ swap / etc .. in LVM's ) no difference between physical or virtual machine :)
So the next question that popped up a couple of minutes later was , wouldn't that be more confusing and complex than managing just some partitions ?
Wouldn't the overview become more complex ?
Actually the overview will be VERY clear if you use the correct naming conviention :)
Say you don't use LVM .. after six months would you still recall if you used /dev/sda9 for / and /dev/sda10 for /usr and if you did that for vhost or vhost2 .. ?
However say you have a volume group "virtual_machines" and in that volume group you have a logical volume called vhost1.root vhost2.usr
which one would you prefer ?