On 2008-04-04T17:34:04, Junko IKEDA <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I am running one test for a split brain like this;
>
> (1) start Heartbeat (node-a/node-b)
> (2) run Dummy resource on node-a
> (3) down the interconnect LAN -> a split brain
> (4) stop Heartbeat (only node-b)
>
> It might be just a little tricky, I modified Dummy RA on node-b as it could
> "sleep 10" when monitor_0 (= prove) was called.
>
> (5) start Heartbeat (only node-b. Heartbeat keeps running on node-a, Dummy
> is running on node-a)
> (6) A split brain is still ongoing, so Dummy would start on node-b, despite
> it's on node-a.
> (7) Dummy on node-a would sleep 10 seconds before starting... I restored the
> interconnect LAN at the exact moment.
>
> There are two results:
> (case-1) ... hb_report_1
> Heartbeat can recover a split brain successfully.
> Dummy would go to one side.
>
> (case-2) ... hb_report_2
> Heartbeat can not recover a split brain.
> The each node can not let another one be added to the membership.
> This is a rare case and hard to reproduce but possible.
>
> See attached hb_report_2/node-b/ha-log.
> Heartbeat noticed that the interconnect LAN was up during a split brain.
>
> heartbeat[9216]: 2008/04/04_16:27:22 info: Link node-b:eth2 up.
> heartbeat[9216]: 2008/04/04_16:27:23 info: Link node-a:eth2 up.
>
> but it didn't consider its partner as a member...
> instance ID is wrong again.
> crmd[9229]: 2008/04/04_16:27:23 info: ccm_event_detail: NEW MEMBERSHIP:
> trans=2, nodes=1, new=0, lost=0 n_idx=0, new_idx=1, old_idx=3
That's a ccm bug.
I guess it can be prevented by using STONITH ;-)
Regards,
Lars
--
Teamlead Kernel, SuSE Labs, Research and Development
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde
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