Dear all,
On *Wednesday September 25th 2024*, the SRE team will run a planned datacenter switchover, moving all wikis from *eqiad* to *codfw*.
This is an important periodic test of our tools and procedures, to ensure the wikis will continue to be available even in the event of major technical issues in our primary home. It also gives all our SRE and ops teams a chance to do maintenance and upgrades on systems in *eqiad* that normally run 24 hours a day.
The switchover process requires a brief read-only period for all Foundation-hosted wikis, which will start on *Wednesday September 25th 2024 @ 15:00 UTC* [0], and will last for just a few minutes while we execute the migration as efficiently as possible. All our public and private wikis will be continuously available for reading, as usual, but editing will be unavailable during the process. Users will see a notification of the upcoming maintenance, and anyone still editing will be asked to try again in a few minutes.
MoveComms will soon begin notifying communities of the read-only window.
If you like, you can follow along on the day in the public *#wikimedia-operations* channel on IRC. To report any issues, you can reach us in *#wikimedia-sre* on IRC, or file a Phabricator ticket with the #datacenter-switchover tag [1]. We'll be monitoring closely for reports of trouble during and after the switchover. The switchover and its preparation will be tracked under [2].
On behalf of the SRE team, please excuse the disruption, and we would like to thank everyone in various departments who are involved in planning this work. If you have any questions, please reply directly to this email.
Kind Regards, Scott French
[0] https://zonestamp.toolforge.org/1727276400
[1] https://phabricator.wikimedia.org/maniphest/task/edit/form/1/?projects=Datac...