Freed memory
Last reboot has been over 4 month ago:
$ sho sys/noproc
OpenVMS V8.3 on node DIANA 27-FEB-2014 07:09:48.67 Uptime 132 13:58:08
and during that time. allocatied virtual memory increased to over 50%. Main users are probably the spam filter (the recommendation is to have 1Gb of memory, but I have only half, so it pages out what is not required) and teh MySQL server, mainly caches, I am told.
Both have been restarted this evening, it took just a few minutes (no reboot, of course) and that brought it back to about 10%.
What goes on behind the doors of the (private) data center