Since I upgraded to Roller 0.9.8, this site has crashed twice. Once last night, and once this afternoon. Both appear to be caused by a MySQL failure, followed by an AJP to Tomcat failure. I haven't asked Keith yet, but I do suspect it's a hosting issue, not a software issue.
Update: From Keith:
No problems with the database as far as I can tell from the logs. Uptime on the server is currently 9939830 seconds or 115 days. Is it possible that you are hitting the 20 connection per user max?
Well at least it stayed up through the night, if it goes again then obviously it's Roller 0.9.8 and I'll be reverting back to the last version (a CVS snapshot) I had running.