[Linux-cluster] Quorum

[brem belguebli]

On Fri, 2010-03-05 at 21:18 +0100, mogruith wrote:
> Hi all
> 
> Today, my cluster crashed, then I have several questions to ask .
> 
> 
> - First of all, is there a kind of "heartbeat" on a quorum disk ? If
> yes, it means, I have two heartbeat on my cluster, one by the quorum,
> second one by a network link. Is it right ?
qdisk is definitely a heartbeat vector. Nodes regularly, at configured
interval value, write to a status block which modifies the timestamp. 
cf man qdisk, chapter 2.1 Heartbeating and liveliness determination

> 
> - How to set the heartbeat link in my cluster conf ? Is the "monitor
> link" is a heartbeat when I set an IP adress to my service ? I have 2
> cards just for the heartbeat network and I have two others cards for
> another vlans.
> 
Currently supported, only the clusternode (cluster.conf) corresponding
IP addresses are used for heartbeating.
Multiple heartbeat interfaces, referred as multiring is technicaly
possiblebut not "yet" supported.  
> - I use mkqdisk to configure my quorum disk. My two nodes were able to
> see it (I used mkqdisk -L on each node). My cluster was quorate. But
> when I killed my first node, the second one didn't take the service and
> the cluster told me it was inquorate ( Cluster is not quorate. Refusing
> connection. Error while processing connect: Connection refused). 
> 
If using qdisk in a 2 nodes cluster, two_nodes setting (cluster.conf)
must be =0.
Quorum depends on the number of votes you gave to each node and to the
quorum.
Cluster is quorate if number of active votes > 50% of the expected votes
(greater than)
mkqdisk is not sufficient, the qdisk device must also be defined in the
cluster.conf.  
> Then service was down and cluster was strange. ccsd and qdiskd were
> still running.
> 
> I relocated service manually and everything was right. Service moved to
> a node to another one without any problem.
> 
How could you relocate the server manually if the cluster was not
quorate ?
> Well .. thanks for your help.
> 
> mog
> 
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