In the coming weeks, the Wikimedia Foundation (WMF) will be shifting all Wikimedia wikis into read-only mode for two short periods. This will allow us to test the process for switching to the secondary data center in Texas. This will increase the chance that Wikipedia and all of our sites will always be available, even shortly after a disaster.
The schedule is:
- Wednesday, 19 April 2017 at XX:00 UTC – no editing for 20 to 30 minutes, while they switch from Virginia to Texas
- Wednesday, 3 May 2017 at XX:00 UTC – no editing for 20 to 30 minutes, while they switch back from Texas to Virginia
Wikimedia wikis will be placed into read-only for between 20 and 30 minutes each time. It will not be possible to edit any page on any wiki during these times. You will be able to log in, to check your watchlist, and to read all pages. If you try to edit or save during this time, then you'll get an error message about the wiki being in read-only mode. If and when you get that message, just hang on; you should be able to save your edit once everything is back to normal—but you should also make a copy of it first, just in case.
We do apologize for the disruption. In an ideal world, we'd be able make this switchover without editors even noticing, but limitations in MediaWiki prevent that at this time. This is something we are working to change. We are hopeful that this year's test will be a little faster and a little more predictable than last year's.
The secondary data center in Texas is a full and complete copy of the main data center in Virginia. It is available in case anything takes the latter offline, whether that's weather or a power outage. This two-week test will see the WMF run all of its traffic and services through the Texas center to ensure that it works, and then shift it all back to Virginia. This is akin to making sure that you can actually restore your computer from a backup drive if you needed to, as opposed to finding out one day that your computer just died and the backup you were counting on is missing.
You can follow the schedule over at Wikitech. If the switchover is delayed for any reason, the schedule change will be announced there. We will be running site notices on all Wikimedia sites. Admins may also choose to run a watchlist notice shortly beforehand, like they did here last year.