[DRBD-user] Xen migration with drbd

Lars Ellenberg lars.ellenberg at linbit.com
Tue Apr 29 16:03:47 CEST 2014

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Tue, Apr 29, 2014 at 11:53:46AM +0200, Wouter de Geus wrote:
> Hej folks,
> I'm running two Xen 4.3.2 machines on which I'm running Drbd 8.4.3 (kernel 3.13.6).
> Drbd works fine as a domU storage device (after hacking in phy in the block-drbd script, it only accepted drbd) using the xl toolstack.
> My problem: migrating a host to the other machine.
> It works, but somehow it fails to demote the old host to secondary status, so after the migration has completed (this part works) I have a situation
> with 2 hosts in primary mode.
> Is this a (known) problem in the block-drbd script?
> Is there a newer version of the script somewhere that's better suited for the xl toolstack?

You should have some logs along with this.
Maybe the script correctly "asked" DRBD to become secondary,
but DRBD refused, as it still was "in-use" by "someone".

That someone frequently turns out to be some udev triggered device scan.

Please find the logs,
or add your own "echo >> some-log" style debugging to the script,
then see why it does not work as expected.

Maybe we simply need to add some sleep (or udevadm settle with timeout)
and retry to the drbdadm secondary.

: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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