Have you updated your xDBC driver to FileMaker 11.3.81 and your FMS11Adv to 11.0v3?
This seems to have fixed the memory leak for us.
This is with FMPA, not FMSA. I run a separate FMSA for other sites.
I have tried 11.3.76 (Latest for FMPA) and 11.3.81 (update for FMPS) to no avail.
Note: Happens with FMSA as well. The FMSA server is far lower traffic and it occurs far less often (I expect a correlation).
The difference is on FMSA the process crashes and there is no dialog box to restart it. Has anyone written a cron function to monitor a process and if it fails, restart it?