mongo-scripts

A collection of useful mongo scripts.

MergeChunks.js

This script allows you to merge your empty chunks across your entire cluster. Run the script on a mongos instance attached to 2.6 mongods. The script contains a function that takes the following arguments,

mergeChunks(dbName, collection, keyPattern, sleepValue = 0)

• dbName: Set this to the database name
• collection: Set this to the collection you want to merge chunks in
• keyPattern: Set this to the key pattern, ie { "_id" : "hashed" }
• sleepValue: How long to sleep between each chunk (for backoff) - optional

SplitChunks

This script allows you to split your chunks on a single shard. Useful when a shard contains significantly more data than others. The script is built using ruby on mongoid as it needs to connect to both a mongos and a mongod. The script contains a function that takes the following arguments,

split_chunks(db, collection, key_pattern, shard, primary_mongod, split_min = 10, mongos = "localhost:27017")

• db: The database name to split chunks in
• collection: The collection to split chunks in
• key_pattern: The key pattern used to shard the collection, i.e. {"_id" => 1}
• shard: The id of the shard to split chunks on (check sh.status())
• primary_mongod: The address and port of the mongod i.e. "mongo.example.com:27017"
• split_min: The minimum number of splits required in a chunk to actually split it - optional
• mongos: The address and port of the mongos - optional