All posts by Lewis Cawte

MediaWiki 1.27.0 – Coming Soon!

The team’s activity last week was dominated by technical tasks. In particular, the main focus of the team was preparing for the MediaWiki 1.27.0 upgrade which will be happening soon.

While we’re not in a position to announce the date of the upgrade just yet, the technical team have been working continuously over the week to prepare it. A number of functions have been removed or replaced in this release which affects a larger chunk of our code than normal. In particular, skins and anti-spam tools which need to be updated before we can deploy 1.27.0 on all wikis.

We also pushed the last set of code to production from the 1.26 release which included a number of bugfixes for Aurora, JavaScript loading for a number of skins and i18n updates to point to our new bug tracking tool which we announced recently.

The customer support team continued their tireless work to respond to any queries and help as many users as possible, and our interns are continuing to make great progress on some interesting new project.

You can follow the progress of our upgrade work on Phabricator – Task 90.

Update on Downtime / F.A.Q

This blog post will serve as a update on the downtime as of 16/04/2014 and an F.A.Q on this and other general downtime and related issues.

The Downtime

So initially, sites were down due to high load on the web server, which causes 503 errors that you see. Earlier that day, it turns out that our Varnish caching software had crashed resulting in about 10 hours of downtime overnight. The downtime you are now seeing is different. Due to problems at our host/datacentre, it appears the hardware that the database server on began having problems, and our host migrated the server to a new “node” without shutting down the server. There appears to have been complications with this that resulted in a sizeable amount of data loss and some database corruptions that were very unlikely and unpredicted when we initially went down.

Our Data Is Gone?

That title is what I assumed might be going through your heads as you read the last section. The answer isn’t a simple yes or no. Our host has a backup from about 12 hours prior to the migration of the node which was during the Varnish crash we believe. In addition to that, the current version of our database server is accessible and has some wikis we should be able to export. It is very important you read the following section thoroughly before clicking the link.

We have logs of all actions that we use to fight vandalism and spam. Using these, we’ve mostly determined the potential loss of data. These “loggable actions” are not all edits. They include things from deletions and protections, to upload and patrol logs. (note: files are not stored on the same server, and are unaffected, they will lose their relevant File/Image namespace page)

Link to list of affected wikis

The Plan

So this part of the post isn’t confirmed, we’re still waiting on a reply from our host but we needed to let you guys know the situation and calm the panic.

As it stands, our host have offered to put up a second instance of our database server running from the backup they took. What we then intend to do is extract as many of the affected wiki’s databases that are not corrupt from the primary instance and import them into the backed up server. This should mitigate as much of the loss as possible.

F.A.Q

When will this be done?

We can’t give an E.T.A at the moment as we have to wait for host to confirm the plans and get things set up. The database server back up is a large file and will take time to transfer. Have you ever performed an action on your computer and the estimated time keeps changing? This is why we can’t tell you for certain, but we’ll be working as hard as we can to get the wikis back up as soon as possible.

Is this the same reason you don’t tell us about other downtimes?

Partially. There are always different factors in each type of errors and sometimes its to do with external factors.

Am I affected?

Unless you contributed to any of the wikis listed after 3AM EDT on Monday the 14th of April, it is very unlikely. However preference changes are not logged so if you changed a setting you may have lost that.

So I should backup my own wiki then/Turn back on DumpsOnDemand?

No. It is very very rare we see data loss and the reason we’ve disabled the features as they are a key cause of the 503 memory issues. It puts high load on the server which ultimately results in downtime. It is understandable for you to see this as the perfect excuse to cry for DumpsOnDemand but it causes downtime, and we get into a vicious cycle of people panicking and backing up their wikis, stopping the service for everyone else.

Why don’t you just buy more servers?

Simple answer, we can’t afford to. We have a former staff member who controls a handful of our servers on his personal account as he gets better deals than our current staff and we can provide the most quality for the little money we have.