[mythtv] Problems with using LVM for large storage

[Jon Wanderer]

> One of the main drawbacks I see to an LVM is the inability to upgrade
> a disk.  If I want to pull a 120GB drive out of the LVM and drop in a
> 300 GB, it might actually be possible, but a massive in the arse to
do.

This is actually a straightforward procedure and can be done with your
system up and running. I recently had a disk in my LVM began to fail and
I needed get all of the data off of it. I connected another drive and
added it to the volume group (pvcreate followed by vgextend). Then I got
the LVM to move all of the data off of the bad drive (pvmove) and then
dropped that drive from my volume group (vgreduce). I was able to do all
of this with the filesystem live, mounted and in use.

I've had excellent results just using LVM and XFS. I can add drives and
grow my filesystem while in use (just a pvcreate, vgextend, lvextend and
xfs_growfs) and remove them as above. If one drive fails, I'll use the
repair tools and as I don't have the volumes stripped I should only lose
the files that were on that drive. But that's fine, as I keep everything
I couldn't stand to lose nice and backed up. I thought about going the
symbolic link way, but I really wanted one giant pool of space that all
of the myth components can easily tap into. Plus, I can move my drives
around, switch from one IDE controller to another, etc, and LVM figures
it all out without any reconfiguration.

Cheers,
Jon