![Why Bother?
• Mongo queries enhance Mongoid queries
• Drop to command line when needed
• Game.where(:outcome=>{‘$in’=>[‘winning’
,‘tie’]})
• Game.collection.update({:outcome=>‘win
ning’, ‘$set’=>{:winning=>true}})](https://image.slidesharecdn.com/mongoadmin-110413081833-phpapp01/75/Mongo-admin-ing-6-2048.jpg)
![Replica Set Fun
config = {
_id: 'houstonrb',
members: [
{_id: 0, host: 'localhost:20000'},
{_id: 1, host: 'localhost:20001'},
{_id: 2, host: 'localhost:20002', arbiterOnly: true}]
}
// Start it up
rs.initiate(config);
// Check it Out
rs.status()
// Who’s your daddy?
rs.isMaster()](https://image.slidesharecdn.com/mongoadmin-110413081833-phpapp01/75/Mongo-admin-ing-18-2048.jpg)
Uploaded byJesse Wolgamott
Mongo admin'ing
This document summarizes how to administer MongoDB using the command line interface. It discusses installing MongoDB, using basic commands like finding and saving documents, setting up replica sets for high availability and scaling, performing backups and repairs, and preventing slow queries through proper indexing. Sharding is mentioned as an advanced technique for scaling databases with large amounts of data or write operations.
Mongo admin'ing
- 1. Mongo Admin’ing Jesse Wolgamott twitter: @jwo slides: http://github.com/jwo
- 2. Quick Install • Dev:brew install mongodb • Server: apt-get install mongodb • http://www.mongodb.org/display/ DOCS/Ubuntu+and+Debian+packages
- 3. Don’t Fear the CommandLine Mongoid / Mongo Mapper Ruby Driver Command Line Javascript (mongo)
- 4.
- 5. Command Line Basics usedba db.collection.find({json params}) db.collection.findOne({json params}) db.collection.mapReduce(map,reduce) db.collection.save({json})
- 6. Why Bother? • Mongoqueries enhance Mongoid queries • Drop to command line when needed • Game.where(:outcome=>{‘$in’=>[‘winning’ ,‘tie’]}) • Game.collection.update({:outcome=>‘win ning’, ‘$set’=>{:winning=>true}})
- 7. All Admin is Command Line • Setup Replica Sets • Check on Status
- 8. Replica / Slave/ Journaling “If you aren’t running a replica set, you don’t care about your data” -- Mongo DB dude
- 9. Master / Slave What You’d Expect M Slave Slave Slave
- 10. Master / Slave What You’d Expect M Writes Go Here Slave Slave Slave
- 11. Master / Slave What You’d Expect M Writes Go Here Slave Slave Slave Reads CAN Go Here
- 12. Replica Sets The new Hotness (and Recommended) Primary Secondary Secondary Secondary Arbiter
- 13. Replica Sets The new Hotness (and Recommended) Primary Secondary Secondary Secondary Writes Go Here Arbiter
- 14. Replica Sets The new Hotness (and Recommended) Primary Secondary Secondary Secondary Writes Go Here CAN Read Arbiter
- 15. Replica Sets The new Hotness (and Recommended) Primary Secondary Secondary Secondary Writes Go Here CAN Read Arbiter Nothing Goes Here
- 16. Arbiter? • Arbiters existwhen even number of hosts • They cast votes on primary elections • Can exist on your app server
- 17. Journaling • Added in1.8 • mongod -- journal • Will write out changes to a journal directory • You can restore from journal
- 18. Replica Set Fun config= { _id: 'houstonrb', members: [ {_id: 0, host: 'localhost:20000'}, {_id: 1, host: 'localhost:20001'}, {_id: 2, host: 'localhost:20002', arbiterOnly: true}] } // Start it up rs.initiate(config); // Check it Out rs.status() // Who’s your daddy? rs.isMaster()
- 19. Non-Master Reads error: {"$err" : "not master", "code" : 10107 } OK, so we’ll do: db.getMongo().setSlaveOk() // Awesome
- 20. Backup / Restore mongodump--db houstonrb mongorestore --db houstonrb -c collections --drop --indexesLast DirectoryName * Have all your .bson files in a directory named your database
- 21. Repairing • The DataGobbler -- mongodb likes hard- drive space and won’t give it back • Use mongod --repair to reclaim your space!
- 22. Nightly Plan service mongodbstop && mongod --repair --dbpath /var/ lib/mongodb && service mongodb start rm -f /data/mongodump-backup.tar.bz2 && mongodump - o /data/backups && tar -jcf /data/mongodump- backup.tar.bz2 /data/backups && rm -rf /data/backups/
- 23. Catch Up! • Whena Replica Set gets ‘stale’ • rs.status will remain “5” (Recovering) • On Master, will say “Error RS102 too stale to catch up” • stop mongo on all servers, copy over all data files, including local.*, start all
- 24. Table Scans ==Devil • When you get to 500,000 records, your DB may slow to crawl. • /var/log/mongodb/mongodb.log for logged queries (table scans) • db.collection.getIndexKeys() • Mongoid: rake db:mongoid:create_indexes
- 25. No, Really • I’vebeen surprised LOTS at how often a table scan happens. • Test it out: mongod --notablescan • Stuff will break.
- 26. Sharding • Don’t ShardEarly • Helps in map-reduce • You define a “shard-key”, like lastname from A-H on this shard
- 27. Scaling (Secret Sauce) •Many Shard Masters, even more slaves • Add Shards for write and data size scaling • Add Slaves for read scaling (map-reduce) and redundancy • Sharding is Hard
- 28. Neat Snippets Replication Setup Sharding Setup https://github.com/mongodb/mongo-snippets
- 29. EC2 Notes • Reformatdrive to EXT4 or XFS • Don’t use EBS for long term backups • Can use EBS for setting up replica sets