On 11 Apr 2014, at 22:37, Lars Ellenberg <[email protected]> wrote:
> > please start new threads not as reply to unrelated threads. > (thread hijacking... goole it ...) > > On Fri, Apr 11, 2014 at 10:14:50PM +0200, Bart Coninckx wrote: >> Hi all, >> >> when enabling automated LVM snapshots, do they interfere (or vice >> versa) with the LVM configurations of a nested LVM setup? > > I think you need to elaborate a bit more... > > What would your "nested LVM setup" look like, > and where/how would you do the "automated" snapshots? > > > I've seen problems with LVM, > if you snapshot the LV below DRBD > (which temporarily has to suspend that LV) > while having the DRBD "visible" to the LVM tools > (not filtered out in the device filter of lvm.conf)... > > The tools could end up scanning the DRBD for LVM meta data, > while having the lower LV suspended, which will obviously cause those > tools to deadlock (and DRBD to remain "hung" or blocked as well). > > If you really need a nested LVM setup > where both "layers" are visible to the host > (not in the sense of LV -> DRBD -> virtual machine image, > and then LVM inside that VM) > > I'd recommend to utilize the "LVM_SYSTEM_DIR" environment variable, > and have two (or more) separate lvm.conf with suitable filter settings, > with the "outer" one being the default (and filter out all DRBD), > and any "inner" one(s) only being used explicitly by setting the > respective LVM_SYSTEM_DIR (and filter out everything BUT the > corresponding DRBD). > > hth, > Lars > > > -- > : Lars Ellenberg > : LINBIT | Your Way to High Availability > : DRBD/HA support and consulting http://www.linbit.com > > DRBD® and LINBIT® are registered trademarks of LINBIT, Austria. > __ > please don't Cc me, but send to list -- I'm subscribed > _______________________________________________ > drbd-user mailing list > [email protected] > http://lists.linbit.com/mailman/listinfo/drbd-user Hi Lars, thanks for your answer and time. The kind of LVM setup I'm referring to is that one on http://www.drbd.org/users-guide/s-nested-lvm.html . The reason for this would be to have maximum flexibility in (re)sizing DRBD resources, but maybe that overcomplicates things and I would better stick to LVM on the backing device. Would that interfere with the automated LVM snapshots feature described in http://www.drbd.org/users-guide/s-lvm-snapshots.html ? Thx again, BC
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