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

Ryan Manikowski jeenam at gmail.com
Tue May 11 20:54:14 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 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?

	 Ryan Manikowski

 ryan at devision.us | 716.771.2282

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