I must apologise Rick, but I think I was misled in thinking my recent httpd server issues were due to the forum upgrade. In fact, I think I've
always had httpd server issues, but I masked the problem using
monit in the past. Monit is basically a monitoring process that can be used to watch and restart stuff, which I use for http, mail, ftp, etc. It's so good that I've been running it for a year and pretty much forgot that I had a httpd problem to begin with (hence this thread!). I highly recommend it.
But it just so happened that when I updated to ubbt 5.3, monit stopped running altogether, and so whenever httpd died it was never being automatically restarted. So I took the opportunity to update monit to the latest release and now my forums are ticking over again.
I still have an problem with httpd getting killed on a daily basis, but thanks to monit, it's never down for more than 2 minutes.
One of these days I'll look into tuning apache for better stability. But at this point I'll bow out and trouble you no further with my problem. Cheers, and thanks again for the help!
