We have had during October and November some problems with our vob mounts: a vob looks empty after having been idle (e.g. while starting the workday).
This problem was actually most frequent with /vob/ov, at a time (Oct 15 - Nov 30) when it was not yet in use from every host (through an /opt/OV unix soft link).
Most of the time, the problem could be solved by anybody issuing the command:
ct mount -all
This has not been reported to Rational.
This could have been an indication of automounting the vob tags (instead of only the vob storage areas, as we do).
We hope that it related to our using soft mounts.
No case reported after the upgrade to CC 3.1.1.
Note relating to efficiency:
Long-term MVFS cache efficiency will drop as VOBs are mounted and unmounted. When a VOB is unmounted, the entire MVFS names are flushed. In addition, if a VOB is unmounted and remounted, any file versions which haven't changed and would have been cached will have to be refetched next time they are accessed.