[DRBD-user] protocol B in dual-primary mode

Lars Ellenberg lars.ellenberg at linbit.com
Wed Jan 7 09:53:39 CET 2009

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, Jan 06, 2009 at 02:48:17PM -0800, Michael Moody wrote:
> However, if you still decide you want to do it (clustered filesystem
> caveats ignored), I just did this by changing the drbd.conf, and using
> drbdadm adjust (must be done on both nodes). Though, I did not do this
> with a dual primary, you may need to take one node to secondary
> status.

in dual primary mode, only protocol C is allowed.

cluster file system deals with cache coherence,
DRBD has to deal with storage coherence.
you cannot do that asynchronously.

to do that in protocol B, the receiving node would need to be able to
access data of in-flight requests, which is not implemented.

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

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