If you dont specify any filesystems all filesystems in teh volumn group should be mounted when the volumn group is activated by HACMP, likewise unmounted when deactivated by HACMP.

One of the most common takeover errors is specifying SOME of the filesystems, and then manually mounting another. HACMP will not be able to varyoffvg the volumn group until the manual mount is unmounted. In other words, not specifying any file systems is best practice.