[Linux-cluster] Howto define two-node cluster in enterprise environment

[Andreas Bleischwitz]

Hello list,

I recently ran into some questions regarding a two-node cluster in an
enterprise environment, where single-point-of-failures were tried to be
eliminated whenever possible.

The situation is the following:
Two-node cluster, SAN-based shared storage - multipathed; host-based
mirrored, bonded NICS, Quorum device as tie-breaker.

Problem:
The quorum device is the single-point-of-failure as the SAN-device could
fail and hence the quorum-disc wouldn't be accessible.
The quorum-disc can't be host-based mirrored, as this would require
cmirror - which depends on a quorate cluster.
One solution: use storage-based mirroring - with extra costs, limited to
no support with mixed storage vendors.
Another solution: Use a third - no service - node which has to have the
same SAN-connections as the other two nodes out of cluster reasons. This
node will idle most of the time and therefore be very uneconomic.

How are such situations usually solved using RHCS? There must be a way
of configuring a two-nodecluster without having a SPOF defined.

HP had a quorum-host with their no longer maintained Service Guard,
which could do quorum for more than on cluster at once.

Any suggestions appreciated.

Best regrads,

Andreas Bleischwitz