I've just had a server outage at 4.59AM on Sunday morning, and looking through our uptime records going back to 2006 all except for 4 outages out of 20 occured between 11PM and 6AM. (Only looking at unplanned downtime on web and database servers, not app-servers on an internal LAN.)
Do others also find similar behaviour for their servers? Is this just a fluke?
Edit: It was because so many outages (these are unplanned, not scheduled maintenance, and occured on our hardware, not the ISP's network) have occured between 11pm and 6AM that made me wonder is that just us...
The servers are busiest in terms of visitors between 1PM and about 10PM, while database backups happen throughout the day and a big backup (where compression uses more of the CPU) occurs around 4.30 every morning. But the outages have occured at any time during this window (also these 20 outages are events occuring on 1 of 5 servers or 2 firewalls - about a third of which were result of 2 different machines' hard-drives failing). There is nothing indicating that the server was doing anything specifically because it was the small hours of the morning.