As far as i know SRDF is only a data replication facility, not a failover mechanism.

A (HA-)cluster makes *systems* highly available, specifically IP interfaces and applications. Usually data are *not* made highly available by cluster means, because data are shared between cluster nodes. Data are made highly available by mirroring, RAID-5, etc., but not by cluster means.

This means that data replication is something not in the scope of HACMP in first place and therefore not suitable for somehow substituting cluster facilities.

Having said this: how about building a "semi-automatic failover" solution in script, which does the following:

- monitor the clusters application IP to be online
- once it is not online any more:
- - roll forward the replication to the latest possible point in time, then
- - mount the (hopefully complete) data on your spare system
- - start the application on the spare system
- - initialize an unused interface with the clusters IP address
- - start serving the app via that IP interface.

There will be all kind of details to cover, which even might make this solution impossible - synchronisation problems, a procedure for taking back the app once the original cluster systems come back online, etc.. Still it is worth a try to explore if such a setup might be possible. It is kind of a "clustering for the real poor", so to say.

I hope this helps.

bakunin