[buildd-tools-devel] Bug#494481: [Buildd-tools-devel] Bug#494481: schroot: Ordering of lvm-snapshot-options

[Roger Leigh]

tags 494481 + fixed-upstream pending
thanks

On Sat, Aug 09, 2008 at 04:46:44PM -0400, Timothy G Abbott wrote:
> The lvcreate command requires that the PhysicalVolumePath option be 
> specified after the original logical volume path (primarily, I think, 
> because it's not a getopt option).  Cursory testing (and normal getopt 
> behavior) suggests that any of the other options can be specified in any 
> order.  In /etc/schroot/setup.d/05lvm, the lvcreate command for snapshots 
> is specified as
> 
>    lvcreate $VERBOSE $CHROOT_LVM_SNAPSHOT_OPTIONS --snapshot \
>  		--name "$CHROOT_LVM_SNAPSHOT_NAME" "$CHROOT_DEVICE"
> 
> which places the lvm-snapshot-options from the chroot configuration before 
> the chroot device, and thus prevents specifying a physical volume path.  I 
> think just changing it (and the non-verbose case) to
> 
>    lvcreate $VERBOSE --snapshot --name "$CHROOT_LVM_SNAPSHOT_NAME" \
>  		"$CHROOT_DEVICE" $CHROOT_LVM_SNAPSHOT_OPTIONS
> 
> would allow one to do everything one can do now, with the added benefit of 
> being able to specify which physical volume the snapshot should be taken 
> from.  This is a useful feature because LVM's write performance is 
> supposedly substantially better if the snapshot is on a different physical 
> volume than the original (as it involves fewer disk seeks).

I've made the above change in git, and it will hopefully make it
into a release soon.  Sorry for the delay in getting around to this
one--my PhD is severely limiting my available time, and it got lost.

Please note that I committed this onto the schroot master branch, and
following the filesystem union merge this is slightly broken (sessions
are not correctly written out into /var/lib/schroot/session--there's
some missing options).  As a result, I can't recommend using the
git repo until it's fixed, which should hopefully be soon.  Picking
up the single change is of course possible.


Regards,
Roger

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