We will have a scheduled maintenance window tonight from 7:00pm to 11:00pm PST. This is being tracked in master bug 475602. The following changes will take place:

• 7:00pm PST (0300 UTC) labs.mozilla.com blog updates. We’ll be updating labs.mozilla.com’s blog to pick up code updates. No downtime is expected.
• 7:00pm PST (0300 UTC) developer.mozilla.org / MDC & library.mozilla.org database maintenance. Both developer.mozilla.org and library.mozilla.org will be offline to re-sync database slaves (bug 475477). Duration 30 minutes..
• 7:00pm PST (0300 UTC) versioncheck.addons.mozilla.org & fxfeeds.mozilla.com load balancer change.  We’ll be moving both versioncheck.addons.mozilla.org & fxfeeds.mozilla.com behind the production Cisco ACE/Zeus ZXTM cluster.  For background, see this blog post.  No downtime is expected.

Please let me know if you have any reason why we should not proceed with this planned maintenance. As always, we aim to keep downtime to as little as possible, but unexpected complications can arise causing longer downtime periods than expected. All systems should be operational by the end of the maintenance window.

As mentioned, this maintenance window is tracked in bug 475602. Feel free to comment directly in that bug (or this blog) if you see issues past the planned downtime.