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

Bart Coninckx bart.coninckx at telenet.be
Tue May 11 21:04:19 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 20:54:14 Ryan Manikowski wrote:
> On 5/11/2010 2:47 PM, Bart Coninckx wrote:
> > 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.
> 
> Documentation I have written for Centos 5.x. Someone let me know where
> to post it. howtoforger perhaps?
> 

Definitely.

B.



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