This evening we have seen a significant drive failure affecting Titan MySQL data. We have swapped out the failed hardware and are actively restoring Titan user MySQL data from the available backups. We expect this process to require another 2-5 hours to fully complete because there is a large amount of data to transfer. We will update this blog post as soon as we have more information regarding the resolution of this issue.
(Update @ 5:25AM CDT 5/8/2015)
Titan MySQL service is now restored. MySQL data was restored from our latest available system-wide backup. If you do see any major data loss with your database, let us know and we can check for user-level backups of your database. We would like to thank everyone for their patience during the resolution of this issue.