HA Cluster solution for Linux - which one to use?

Hi all experts,

I need your kind suggestions or feedback on choice of clustering software for red hat linux nodes running certain applications which I need to make highly available.

Minimum requirement is 2 nodes; all nodes shall be active-active running distinct applications e.g. node 1 runs application ABC and node 2 runs application PQR, node 1 is back up node for PQR and node 2 for ABC. Node 1 and node 2 do not have any shared storage required, they access back end database which is protected by Oracle's dataguard.

I need to have cost-effective HA with minimum downtime. There are various HA solutions available in market - SteelEye, Veritas Cluster, Red Hat cluster suite, IBM HACMP etc. and I have almost narrowed down to Red Hat Cluster(for it being cheaper) vs Veritas (for it being feature rich).

Any experiences with clustering? Any pros and cons of these two cluster software (with references would be appreciated) would be of great help?

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There's always Linux-HA with/without pacemaker and or drbd

http://www.linux-ha.org/wiki/DRBD