Mongodump and mongorestore; field not found - mongodb

Question

I'm trying to dump a database from another server (this works fine), then restore it on a new server (this does not work fine).
I first run:
mongodump --host -d
This creates a folder dump/db which contains all of the bson documents.
Then in the dump folder, I'm running:
mongorestore -d dbname db
This works and iterates through the files, but I get this error on dbname.system.users
Wed May 23 02:08:05 { key: { _id: 1 }, ns: "dbname.system.users", name: "_id_" }
Error creating index dbname.system.usersassertion: 13111 field not found, expected type 16
Any ideas how to resolve this?

Answer 1

If it realy different versions, use --noIndexRestore option. And create all index after that.

Answer 2

Any chance the source and destination are different versions?
In any case, to get around this, restore the collections individually using the -c flag to the target DB and then build the indexes afterward. The system collection is the one used for indexes, so it is fairly easy to recreate - try it last once everything else has been restore, and if it still fails you can always just recreate the relevant indexes.

Answer 3

The issue could also caused by this bug in older versions of Mongo (In my case it was 2.0.8):
https://jira.mongodb.org/browse/SERVER-7181
Basically, you get 13111 field not found, expected type 16 error when it should actually be prompting you to enter your authentication details.
And example of how I fixed it:
root#precise64:/# mongorestore /backups/demand/ondemand.05-24-2013T114223/
connected to: 127.0.0.1
[REDACTED]
Fri May 24 11:48:15 going into namespace [test.system.indexes]
Fri May 24 11:48:15 { key: { _id: 1 }, ns: "test.system.users", name: "_id_" }
Error creating index test.system.usersassertion: 13111 field not found, expected type 16
# Error when not giving username and password
root#precise64:/# mongorestore -u fakeuser -p fakepassword /backups/demand/ondemand.05-24-2013T114223/
connected to: 127.0.0.1
[REDACTED]
Fri May 24 11:57:11 /backups/demand/ondemand.05-24-2013T114223/test/system.users.bson
Fri May 24 11:57:11 going into namespace [test.system.users]
1 objects found
# Works fine when giving username and password! :)
Hope that helps anyone who's issue doesn't get fixed by the previous 2 replies!

Answer 4

This can also happen if you are trying to mongorestore into MongoDB 2.6+ and the dump you are trying to restore contains a system.users table in any database other than admin. In MongoDB 2.2 and 2.4 the system.userscollections could occur in any database. The auth schema migration associated with MongoDB 2.6 moved all users into the system.users table in the admin database, but left behind the system.users tables in the other databases (MongoDB 2.6 just ignores these). This seems to cause this assertion when importing into MongoDB 2.6.