Yes well its a pity because if something can go down, it will go down.
So you can put mirrored OS in a system, redundant power, fans, service
processors etc etc..but if the main processor went down or memory or the
backplane etc etc..you cant do anything ..

now in case of ADSM , with the backup windows being so small and all, if
that happens just before or around that time, you are basically without
one days backup until the next night..
HACMP will transfer your volume groups and ip addresses but in casse of
ADSM u need more than that..u need the ADSM server running with all the
customised files and devices...
I wish IBM comes up witha  preferred solution to this