[mythtv-users] OT: xfs_growfs

[Martin Ebourne]

On Tue, 06 Sep 2005 14:49:13 -0400, Jay R. Ashworth wrote:
> I just did this the other day on my sis's box.  The process was, roughly,
> this:
> 
> 1)	Unplug DVD-R (hdd), plug in new Seagate 400GB
> 2)	Boot up, fdisk new hdd1 as LVM (8e) with same parameters as
> 	hdc1 we want to move from the 200GB to the 400GB (only 2.5 drive bays in
> 	case)
> 3)	dd if=/dev/hdc1 of-/dev/hdd1 bs=10MB (this took about 12 hours
> 	for 187GB; I'd use 100MB and a double buffering dd if I had it to do
> 	again).
> 4)	Shut down and swap back to DVD-R hdd and 400GB hdc. 5)	Boot up, go into
> YaST (this is SuSE 9.0), and make sure hdc1
> 	shows up as part of the VG (it did).
> 6)	Ran lvm's option to check the integrity of the VG (forget name;
> 	was ok).
> 7)	Create new /dev/hdc2 filling disk
> 8)	Add hdc2 to VG

This is not a good way to do things. With this method you end up with two
PVs on one disk in the same VG. Strongly not recommended.

Here's a better way:

1. Reboot with new disk /dev/hdd
2. Partition the whole disk as lvm
2. pvcreate /dev/hdd1
3. vgextend VG /dev/hdd1
4. pvmove /dev/hdc1 /dev/hdd1
5. vgreduce VG /dev/hdc1

This way you end up with one PV filling the whole new disk. And the best
bit (especially for a mythtv box) is that the system is 100% available the
whole time, INCLUDING the LVs being moved from one disk to the other,
which can stay mounted and fully available all the way.

I moved a whole load of LVs round recently using pvmove, and at one point
I had two recordings into and one playback out of an LV while it was being
moved. All worked great.

Cheers,

Martin.