advice on PGSQL cluster (active/passive)

[FM <dist-list@xxxxxxxxxxxxxxxxxx>]

Hello,
Next month I will receive my SAN and a new server. Using Redhat Cluster 
Suite + GFS, I'd like to create a PGSQL active/passive cluster.

Do you have some advice about this setup or advice for PGSQL Clustering ?
For now, we are using 7.4.x but we will migrate to 8.1.x

My passive server will be a VMWare Virtual host with the same amount of 
memory then the active  node.

Thanks !