1. Expense of the software and having a second server that basically does nothing.
2. It complicates the system design.
3. Have to have someone who knows HACMP.
4. Have to run regular tests – takes planning and downtime.
5. Only failed over once in four years on the old system.
Because the IBM pServers are so reliable these days, it seem that the risk of hardware failure is minimal. We made the system as fault tolerant as possible – dual power supplies, dual cooling fans, dual ethernet adapters, dual fibre channel adapters to our SAN (we do not use internal disk in production), and so on. We have been on this configuration for 1.5 years and have not had a hardware filaure.
