When upgrading to mongodb 3.0, should I upgrade authentication schema after upgrading the storage engine to WiredTiger?
As part of the MongoDB 3.0 upgrade it is strongly recommended that you upgrade to the SCRAM-SHA-1 authentication scheme. New users will have their credentials created in this format by default; mixed authentication schemas will likely lead to confusion.

You will need to upgrade your client driver &amp; admin tools (if you're using a GUI) in order to use the WiredTiger storage engine. Drivers/tools that have been updated for MongoDB 3.0 will also support the new authentication method.

As per the note on the SCRAM-SHA-1 documentation (referring to a future major release which would like be 3.2.x):


  The next major version of MongoDB is likely to remove all support for MONGODB-CR.