This document discusses using MongoDB as a caching system. It outlines some traditional in-memory and centralized caching systems, and then describes MongoDB's advantages for caching - including support for time to live (TTL), high availability, scalability and easy use. It also covers testing MongoDB caching performance through stress tests of a sample application, and obtaining results of 1300 requests per second with 5 millisecond average response times. Tuning techniques for MongoDB caching are also mentioned.

1. Caching with MongoDB
Charles Blonde
Guillaume Arnaud
Pablo Lopez

2. Other caching systems
In memory Centralized
 EHcache  Memcached
 Gemfire  Redis
 Gemfire
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3. The needs
 Switching from statefull EJB to Web services : sessions
caching
 Highly available
 Speed & Multipurpose
 High volumes
 Future : replace existing cache systems
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4. MongoDB as a caching system
Pros Cons
 TTL Support in MongoDB  Speed
2.2
 Disk usage
 Higly available
 Scalable
 Automatic failover
 Easy to use
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5. Testing
 Writing a Tomcat valve and a sample Web application
 Setting up an environment :
▶ 1 MongoDB Replicaset
▶ Between 2 and 6 applications servers
▶ 1 load balancer
 Stress tests
 Results
▶ 1300 req/sec => 5ms avg
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6. Tuning
 Disable journaling
 Write concern /read preferences
 Oplog sizing
 Sharding ?
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