On 12/09/2013 11:20 PM, ToddAndMargo wrote:
>> then you absolutely want to be running
>> them against a snapshot rather than a live FS and LVM makes this easy.
>
> Never really cared for LVM.  Always used the direct partition approach.

Well, perhaps I can try to convince you some more.

Take another example of upgrading to a bigger disk.  Huge PITA if you 
use direct partitions.  Shut the system down and use a live OS or 
something while you move over all the data -- which could take hours or 
days depending on what you need to move.  If you are really obsessive 
you probably want to make sure nothing got lost in the move so there is 
a whole compare exercise after it finishes.

If you have LVM you simply install your new drive (assuming you can 
hotswap you don't even have to shutdown for that) run pvcreate, vgextend 
and then pvmove.  Some hours (or days) later it finishes and your data 
is magically on the new disk without even a moment of downtime.

A lvextend and a resize2fs (or whatever utility resizes the FS you use) 
and you can start using the extra space, still with no downtime.

That is pure sysadmin gold!

BTW: I also use LVM on my offsite backup disks.  I just use the same 
volume group/volume name on all the disks.  Works with LUKS also.

Jeff