mongorestore failing because of DocTooLargeForCapped error - mongodb

Question

I'm trying to restore a collection like so:
$ mongorestore --verbose --db MY_DB --collection MY_COLLECTION /path/to/MY_COLLECTION.bson --port 1234 --noOptionsRestore
Here's the error output (timestamps removed):
using write concern: w='majority', j=false, fsync=false, wtimeout=0
checking for collection data in /path/to/MY_COLLECTION.bson
found metadata for collection at /path/to/MY_COLLECTION.metadata.json
reading metadata file from /path/to/MY_COLLECTION.metadata.json
skipping options restoration
restoring MY_DB.MY_COLLECTION from file /path/to/MY_COLLECTION.bson
file /path/to/MY_COLLECTION.bson is 241330 bytes
error: write to oplog failed: DocTooLargeForCapped document doesn't fit in capped collection. size: 116 storageSize:1206976512 # 28575
error: write to oplog failed: DocTooLargeForCapped document doesn't fit in capped collection. size: 116 storageSize:1206976512 # 28575
restoring indexes for collection MY_DB.MY_COLLECTION from metadata
Failed: restore error: MY_DB.MY_COLLECTION: error creating indexes for MY_DB.MY_COLLECTION: createIndex error: exception: write to oplog failed: DocTooLargeForCapped document doesn't fit in capped collection. size: 116 storageSize:1206976512 # 28575
The result of the restore is a database and collection with correct names but no documents.
OS: Ubuntu 14.04 running on Azure VM.
I just solved my own problem. See answer below.

Answer 1

The problem seemed to be that I was using mongod on the replica set PRIMARY member.
Once I commented out the following line in /etc/mongod.conf, it worked without problems:
replSet=REPL_SET_NAME --> #replSet=REPL_SET_NAME
I assume passing the correct replica set name to the mongorestore command (like in this question) could also work, but haven't tried that yet.