Michael DelNegro is a principal database administrator at AOL who has been administering MongoDB databases for applications including MapQuest and Patch. He provided an overview of MongoDB and tips for administering MongoDB databases effectively, as well as resources for further learning.

1. Administration
Michael DelNegro
Principal Database Administrator
AOL
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2. Presentation Overview
• Introduction
• My Applications
• Tips
• Tools
• Resources
• Upcoming
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3. About Me
• DBA at AOL (Dulles) for six years
• Background in Sybase
• Now MySQL, PostgreSQL and NoSQL
• Was: Blogsmith, Uncut Video, Travel, Autos,
Journals, Real Estate, Ficlets, Shopping
• Currently: Patch, MapQuest, HSS,
Datalayer, Demand
• I Heart Big Data
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4. About MongoDB
• “Scalable, high-performance, open source,
document-oriented database”
• Databases (Databases)
• Collections (Tables)
• Documents (Rows)
• Fields (Columns) - K/V Pairs
• Indexes
• No Joins
• Favors Embedding Data instead of FKs
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5. More About MongoDB
• JSON-style Documents
• Javascript Shell
• Capped Collections
• Flexible Schemas
• Replication w/ Autofailover
• Sharding
• GridFS: File Storage
• Map-Reduce 5

6. MongoDB Support
• Operating Systems
• Linux, Windows, Mac OS X, Solaris
• 32bit, 64bit
• Drivers
• Java, Javascript, Perl, Ruby, Scala, Erlang, C,
C#, C++, Haskell, PHP, Python
• R, Smalltalk, node.js, ColdFusion
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7. MongoDB Use Cases
• Website Data Store
• Caching Tier
• Document and Content Mgmt Systems
• Event Logging
• Real-time Stats/Analytics
• Archiving
• High Volume Problems
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8. MongoDB Misuse
• Complex Transactional Systems
• Traditional Business Intelligence
• SQL is a Must
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9. MongoDB at AOL
• In use since Summer 2010
• I currently administer two applications for
MapQuest and Patch
• There are other MongoDB applications in
use throughout the company and more on
the way
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10. MapQuest App
• Tracks User Profile Information
• V. 1.6.5.latest (just upgraded from 1.6.3)
• 26 Total Hosts, CentOS 5, 16GB RAM
• 300 million users, 130 million saved maps
• Replica Sets
• 3 Sharded Collections
• lookup, east coast, west coast
• Java 10

11. Patch App
• Tracks User Activity
• Master, 2 Slaves
• V. 1.6.3
• About 100GB of data
• Throwaway Data (for now)
• Ruby on Rails
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12. About Patch
• “HyperLocal” news sites across the
country
• Fills gap in coverage left by local
newspapers
• Currently 800 sites are live
• 1000+ by end of 2011
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13. Nearby Patch Sites
• Vienna (ex. vienna.patch.com)
• Ashburn
• Reston
• McLean
• CollegePark
• GreaterAnnapolis
• 50+ in DC Area
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14. Upcoming Ops Plans
• Upgrade to 1.8
• Migrate Patch to Replica Sets
• Move MapQuest to bigger hardware (16GB
-> 64GB memory)
• Add additional slaves
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15. Admin Tips
• Slaves are a MUST pre1.8
• Use 64 bit version
• 32 bit version has 2.5 GB storage limit
• Use xfs or ext4
• Keep eye on oplog size
• Turn off atime & dtime
• Consider using getLastError()
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16. More Admin Tips
• Increase File Descriptor Limits
• Do not use kill -9 (pre-1.8)
• Consider having a slave on replication delay
• -- slavedelay <seconds>
• db.runCommand(“logRotate”)
• Keep db.<collection>.totalIndexSize() less
than RAM
• Linux dirty_background_ratio and
dirty_ratio (pre 2.6.22)
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17. Even More Admin Tips
• Omit parenthesis to see command details
• 5 Primitives of Mongo
• insert, remove, update, find, getMore
• Replication is a slave polling master process
• Master and slaves each have their own
oplog
• Choose shard key carefully (ex. timestamp)
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18. Admin Tools
• mongodump-mongorestore
• use fsync and lock database to ensure
consistent backup
• fsync and lock are a must for file system
backups (ex LVM)
• http://localhost:28017 (server port + 1000)
• db.currentOp()
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19. More Admin Tools
• mongostat
• db.printReplicationInfo()
• db.serverStatus()
• db.<collection>.stats()
• Database Profiler
• Explain
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20. Admin Resources
• mongodb.org
• Events
• Forums
• Wordnik Mongo Admin Tools (Github)
• Mongo Snippets (Github)
• IRC (freenode #mongodb)
• Little MongoDB Book
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21. More Admin Resources
• slideshare (Use Time-Based Search)
• GUI Admin Tools
• MongoVUE
• Others
• Kristina Chodorow's Blog
• Boxed Ice
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22. Even More Resources
• Follow @MongoQuestion (StackOverflow)
• MongoDB on Quora (@q_mongodb)
• 10gen Deployment Strategies Slides
• Books
• Training
• 10gen Support
• Office Hours in NYC and Redwood City
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23. New MongoDB Release
• 1.8 (Released March 16)
• Single Server Durability (Journaling)
• Enhancements to Sharding & Replica Sets
• Covered and Sparse Indexes
• Tab Completion
• Maximum BSON Document: 16MB
• 1.8 Features Presentation
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24. Future Releases
• 2.0 (May/June?)
• Better Map-Reduce and Aggregation
• Improved Concurrency
• Online Compaction
• TTL Time-Out Collections
• Beyond
• Full-Text Search?
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25. Thank You!
• www.slideshare.net/radiocats
• @radiocats on Twitter
• www.linkedin.com/in/mdelnegro
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