[DRBD-user] DRBD primary/primary for KVM - what is the best option?

Bart Coninckx bart.coninckx at telenet.be
Tue May 11 20:47:05 CEST 2010

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


On Tuesday 11 May 2010 19:28:46 Ryan Manikowski wrote:
> On 5/11/2010 1:12 PM, Michael Iverson wrote:
> > The interesting bit on the first link was the statement:
> >
> > "If active-active isn't possible, maybe there is distance involved and
> > it's doing asynchronous replication, then you will need to implement
> > something like heartbeat to add the volume using ietadm to the running
> > iSCSI target once drbd B becomes primary..."
> >
> > The quote is a little short on implementation details, but based on
> > it, and some snippets
> > from the other links, it is the tool to dynamically add or remove
> > volumes without messing
> > with the remainder of the live volumes.
> >
> > The only challenge I see is that any changes that are made are
> > dynamic, and would not
> > survive a reboot or a daemon restart. So, somehow, upon a restart, the
> > ietd daemon needs
> > a method to reliably determine which volumes it should or should not
> > be serving, or be
> > told what to server by heartbeat or the state of the drbd volume.
> 
> A bit off topic, but instead of using IETD as the target daemon, using
> SCST will provide better performance. Also, for those looking into using
> a drbd/heartbeat/iscsi solution to host Microsoft Hyper-V clusters, SCST
> offers SCSI-3 compliant Persistent Reservations. IETD, to my knowledge,
> does not support PR.
> 

True, but the integration with Heartbeat and SCST is poorly documented. 
Recently I found only one  reference to a howto. 

B.



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