Weirdest bug I saw was OTRS getting slow at the end of the month. It was weird, no pressure on the DB or the server, it would get slow with barely any users and

Weirdest bug I saw was OTRS getting slow at the end of the month. It was weird, no pressure on the DB or the server, it would get slow with barely any users and then suddenly it would work really fast with no change. After a wild goose chase I saw one of the servers took too long to authenticate SSH than the other when the problem happend, turns out, the only difference between the 2 was one of them had a reference to a domain and the other did not. From this clue I checked there was an internal AD server that was getting called by its domain name on every page call of OTRS. When that DNS server got slow, each page got slow, switching to direct IP fixed it. DNS getting slow on an internal system is wayy down on most people's lists if it even exists..