* [Cluster-devel] qdisk and fence race
@ 2013-02-13 17:32 Dietmar Maurer
2013-02-18 19:33 ` Lon Hohberger
0 siblings, 1 reply; 3+ messages in thread
From: Dietmar Maurer @ 2013-02-13 17:32 UTC (permalink / raw)
To: cluster-devel.redhat.com
The following example is copied from 'man qdisk':
<cman two_node="0" expected_votes="3" .../>
<clusternodes>
<clusternode name="node1" votes="1" ... />
<clusternode name="node2" votes="1" ... />
</clusternodes>
<quorumd interval="1" tko="10" votes="1" label="testing">
<heuristic program="ping A -c1 -w1" score="1" interval="2" tko="3"/>
</quorumd>
Is it true that this can still result is a fence race?
If so, what is the suggested way to avoid that? Should I configure with master_wins="1" instead?
^ permalink raw reply [flat|nested] 3+ messages in thread* [Cluster-devel] qdisk and fence race
2013-02-13 17:32 [Cluster-devel] qdisk and fence race Dietmar Maurer
@ 2013-02-18 19:33 ` Lon Hohberger
2013-02-19 4:51 ` Dietmar Maurer
0 siblings, 1 reply; 3+ messages in thread
From: Lon Hohberger @ 2013-02-18 19:33 UTC (permalink / raw)
To: cluster-devel.redhat.com
On 02/13/2013 12:32 PM, Dietmar Maurer wrote:
> The following example is copied from 'man qdisk':
>
> <cman two_node="0" expected_votes="3" .../>
> <clusternodes>
> <clusternode name="node1" votes="1" ... />
> <clusternode name="node2" votes="1" ... />
> </clusternodes>
> <quorumd interval="1" tko="10" votes="1" label="testing">
> <heuristic program="ping A -c1 -w1" score="1" interval="2" tko="3"/>
> </quorumd>
>
> Is it true that this can still result is a fence race?
>
> If so, what is the suggested way to avoid that? Should I configure with master_wins="1" instead?
It's best to use master_wins over a heuristic. Ping as a tiebreaker
seems good in practice, but the problem is that there are certain
network failures where two nodes can see the thing they're pinging - but
not each other (e.g. some switch loops).
master_wins protects against this.
-- Lon
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Cluster-devel] qdisk and fence race
2013-02-18 19:33 ` Lon Hohberger
@ 2013-02-19 4:51 ` Dietmar Maurer
0 siblings, 0 replies; 3+ messages in thread
From: Dietmar Maurer @ 2013-02-19 4:51 UTC (permalink / raw)
To: cluster-devel.redhat.com
> > If so, what is the suggested way to avoid that? Should I configure with
> master_wins="1" instead?
>
> It's best to use master_wins over a heuristic. Ping as a tiebreaker seems
> good in practice, but the problem is that there are certain network failures
> where two nodes can see the thing they're pinging - but not each other (e.g.
> some switch loops).
>
> master_wins protects against this.
Ok. Many thanks for your help.
- Dietmar
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-02-13 17:32 [Cluster-devel] qdisk and fence race Dietmar Maurer
2013-02-18 19:33 ` Lon Hohberger
2013-02-19 4:51 ` Dietmar Maurer
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