We have been experiencing intermittent Bugzilla slowness since Wednesday, June 12th 2013 at 5 pm UTC (10 am US/Pacific time). We have been working throughout the weekend to pinpoint the cause of this irregular, but noticeable, issue. The problem is performance only, there have been no reports and no evidence of data or functionality loss. We will release additional information as we have it.
Update 18 Jun 2013 18:40 pm UTC: The Phoenix chassis outage was completely unrelated to this Bugzilla slowness. Bugzilla is in a different data center and neither caused nor affected the chassis problem, and the only effect the chassis problem had was to pull resources away from figuring out and fixing the bugzilla issue.