Another failure with my V6.1.0.2 server.

This morning the ONLY user (a total of 3-active nodes) of my V6.1.2.0
server reported his backups failing with his dsmerror.log showing:
10/26/2009 23:21:15 ANS1316E The server does not have enough recovery log
space to continue the current operation
The activelogsize is set to 60000 and I run 3-FULL DB backups daily
(followed by BACKUP VOLHIST).  This mornings check shows the log at under
200MB used (a full DB backup had already run at 22:00:00).
How big do I need to make this?  Should I max it out at 128G?
What are your experiences/settings for activelogsize, for folks running a
V6 server in production?