Archive for the ‘MongoDB’ Category

Restart your Mongos after maxConsecutiveFailedChecks

Take it literally. If you configured your MongoDB config servers as a replica set and for some reason, say a network outage, Mongos server lost connection to all of them and is not able to reconnect during maxConsecutiveFailedChecks attempts then, surprise, it becomes useless. Even if the network is up and running again, Mongos will […]

Posted on February 9, 2017 at 5:03 pm by sergeyt · Permalink · Leave a comment
In: MongoDB

jbd2 is munching your disks? Use ftrace to find why.

Have you ever been wondering why jbd2 (or jbd if your are still using ext3) is sitting at the top of iotop and consuming the most of IO bandwidth? Well, it’s certainly not because it’s doing that just to drive you nuts but there is a reason. And the reason is most probably there is […]

Posted on January 27, 2017 at 11:51 am by sergeyt · Permalink · Leave a comment
In: Linux, MongoDB

MongoDB – Defeating RangeDeleter

Not closing a cursor in MongoDB could hurt you big, so it’s generally not recommended to use no_cursor_timeout=True (pymongo3) or timeout=False (pymongo2). Especially when you run shared MongoDB installation: PyMongo does “close” cursors when they are garbage collected, but they aren’t closed immediately and closing a cursor in all current versions of MongoDB is asynchronous. […]

Posted on January 19, 2017 at 7:47 pm by sergeyt · Permalink · Leave a comment
In: MongoDB