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[Linux-cluster] Cluster stability with missing qdisk


In the clusters we have we use a qdisk to determine which node had the quorum, in case of a split brain situation.

This is working great... until the qdisk itself is hit due to problems with the SAN. Is there a way to have a stable cluster,
with qdisks, where the absence of (1) qdisk won't kill the cluster all together. At this moment, with the setup with 1 qdisk,
the cluster is totally depending on the availability of the qdisk, while, IMHO, it should be expendable.

We have now a triangle setup, with 2 data centers and 1 extra 'quorum' location for the IBM SAN. In the SAN setup there
are 3 quorum devices, 1 in each data center and the 3rd on the quorum location. When 1 location fails (one of the data
centers or the quorum location) it is still up and running.

Is it possible to copy this setup and use 3 qdisks, so when 1 qdisk fails the cluster stays alive? I would set the vote
value of all components (systems and qdisks) to 1, so the cluster would keep running with 2 systems and 1 qdisk
or 1 system with 2 qdisks. (it'll be dead with only 3 qdisks, as the software will die with both systems ;) )

I've heard of setup's with 3 systems, where the 3rd was just for the quorum, so you this one can die, but on this
occasion it won't help us, as there are no systems on the 3rd location. (and it's not supported by Red Hat, when I'm
correctly informed)

With regards,
Inter Access BV

ing. J.C.M. (Jan) Huijsmans
Designer / Technical Consultant UNIX & Linux
Infrastructure Professional Services UNIX

E-mail:  jan huijsmans interaccess nl

Tel:     035 688 8266
Mob.:    06 4938 8145

Colosseum 9, 1213 NN Hilversum
Postbus 840, 1200 AV Hilversum
K.v.K. Hilversum 32032877

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