Summary: Yesterday’s maintenance period was completed and successful, but we ran into a problem that left us with a longer-than-expected period of read-only access (~5:00pm to 11:30pm PDT), as well as a few other side effects. We have already addressed these issues, but we would like to explain the situation for any users who were bothered by last night’s difficulties.
The following is slightly technical. If you are already bored or haven’t run into any problems using Khan Academy, feel free to ignore.
We had two primary goals for last night’s maintenance period:
- Fix the occasional “Server Error” pages that users have been seeing randomly.
- Fix some of the frustrating slowness users have been experiencing.
These two problems are related, and we needed to swap out a large piece of our technical infrastructure* to properly address the root cause. Hence the need for our read-only period.
Most of this transition went very smoothly. We put up an explanatory landing page that you may have seen, telling users, “We’ll be back soon.” Unfortunately, right when we were about to finish, we realized that we made a mistake with that “We’ll be back soon” page**. Due to this mistake, we were unable to get rid of that page and replace it with the fully functioning version of Khan Academy.
Once we realized this, we had to pull a number of time-consuming tricks*** to get the site back up and running. These tricks caused the extra delay, and it also left a few side effects that you may have noticed today:
- When visiting www.khanacademy.org, users were redirected to khan-academy.appspot.com. This is perfectly safe, and it was only a temporary solution that we have now fixed.
- Some users may continue to see the “We’ll be back soon” page long after we restored full functionality late last night. These users need to reload the www.khanacademy.org page, and then they should be all set.
- If you experienced or continue to experience issues with the site that you think are connected to last night’s maintenance period, please comment on this post and we will work quickly to help you resolve your problem.
We apologize for all of the trouble, but there’s an upside.
The good news!: the original goal of the maintenance period was, at first glance, very successful. We will keep you up-to-date, but all evidence on our end suggests that www.khanacademy.org is now running much faster (woohoo!) and much more reliably (you shouldn’t see any more ugly “Server Error” pages) than before.
Thanks for your patience and understanding. We’ll continue to update you as we work to keep www.khanacademy.org chugging as quickly and smoothly as possible.
- * We were switching to Google’s new, highly improved High Replication datastore.
- ** We mistakenly set a far-future Expires header for the maintenance page. This caused a cascading series of caching issues between us and our users.