[Linux-cluster] Re: CS5 / About qdisk parameters

Alain Moulle Alain.Moulle at bull.net
Fri May 16 07:56:14 UTC 2008

Hi Lon

Sorry Lon, but it is not completely clear again for me ... :

when you write that default cman timeout on RHEL5 is 5 seconds, you
mean that the heart-beat timeout is 5s ? whereas each hello message is
sent every 5s too ?
And the totem in cluster.conf to modify it was in my understanding the
"deadnode_timer" in the cman record ... what is the "token" you mention ?

And finally, my would be to set deadnode_timer="21s" for cman and to keep
interval="1" and tko="10" for quorum disk.

Just a precision, it on a only two nodes cluster with quorum disk.

Thanks to confirm these points.

Alain Moullé

> Yes, but you don't want to match it.

> You want qdisk to timeout before CMAN with enough time so that ifthe
> qdisk master node dies, there is enough time to elect a new master
> *before* CMAN would normally transition.

> On RHEL4, the default CMAN timeout is 21 seconds.

> On RHEL5, it's 5 seconds - which must be tweaked currently using the
> totem <token ... > parameter.

> I intend to make qdiskd automatically detect the CMAN death detection
> time in the near future and automatically configure itself, because this
> is something users/administrators just *shouldn't* have to deal with...

> (Does anyone disagree with that?   :)   )

> Anyway, here's a graphical representation as to why qdiskd needs to time
> out (long) before CMAN:

> http://people.redhat.com/lhh/cmanvsqdisk.png

> -- Lon

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