problem likely solved
Ok, thanks for this. I added 'ocfs2' as indicated. I also added the path to our SAN, '/ocfs2SAN', to Prunepaths for good measure. While I still have problems with other processes hanging at 6:25 in the morning, updatedb is no longer one of them. Your comments were very helpful as they put me onto possibility that the suite of daily cron jobs (cron.daily), scheduled for 6:25 in the morning are either hanging up or causing ocfs2 and the SAN connection to hang up. Perhaps they are hanging for the reason you mentioned: that the SAN is overloaded at that time. (which could conceivably owe either to daily backups being run then or else perhaps a bunch of new Debian Squeeze installs on several of our boxes all running their cron.daily jobs at the default time of 6:25 a.m. I am running the cron.daily jobs on the test box every 30 seconds to test possible conflict with the ocfs2-network stress test and now, during the workday, I am not encountering any problems.