PowerHA is the new name for HACMP, which is short for High Availability Cluster Multi-Processing, a product of IBM. PowerHA / HACMP runs on AIX (and also on Linux) and its purpose is to provide high availability to systems, mainly for hardware failures. It can automatically detect system or network failures and can provide the capability to recover system hardware, applications, data and users while keeping recovery time to an absolute minimum. This is useful for systems that need to be online 24 hours a day, 365 days per year; for organizations that can't afford to have systems down for longer than 15 minutes. It's not completely fault-tolerant, but it is high available.

Compared to other cluster software, PowerHA / HACMP is highly robust, allows for large distances between nodes of a single cluster and allows up to 32 nodes in a cluster. Previous version of PowerHA / HACMP have had a reputation of having a lot of "bugs". From version 5.4 onward PowerHA / HACMP has seen a lot of improvements.

IBM's HACMP exists for over 15 years. It's not actually an IBM product; IBM bought it from CLAM, which was later renamed to Availant and then renamed to LakeViewTech and nowadays is called Vision Solutions. Until August 2006, all development of HACMP was done by CLAM. Nowadays, IBM does its own development of PowerHA / HACMP in Austin, Poughkeepsie and Bangalore.

Competitors of PowerHA / HACMP are Veritas Cluster and Echo Cluster. The last one, Echo Cluster, is a product of Vision Solutions mentioned above and tends to be easier to set-up and meant for simpler clusters. Veritas is only used by customers that use it already on other operating systems, like Sun Solaris and Windows Server environments, and don't want to invest into yet another clustering technology.



If you found this useful, here's more on the same topic(s) in our blog:

• Quick setup guide for HACMP
• Reservation bit
• Email messages from the cron daemon
• Tweaking the deadman switch
• PowerHA HTML report