Amazon DynamoDB
- NoSQL service
- Built on SSDs
- No storage limits
- performance, durability, availability, scalability
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key value, no schema
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key options: hash key lookups, or composite keys
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Strong or eventual consistency -- you get to pick
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Writes acknowledged nly when on disk in two AZs
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Not worrying abiout memory, CPU, etc... you pick what your app needs in terms of latency, throughput, etc
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You provision write and read capacity. You say what you want. No concern for storage.
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Can change given your needs
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Can match capacity to traffic; don't need to worry about forecasting as much as before
- Scaling
- Automatic sharding
- Security, patches, upgrades
- Automatic hardware failover
- Multi-AZ replication
- ...
Try: http://aws.amazon.com/dynamodb
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User metadata DB for error reporting, etc
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Started with MongoDB
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Expensive to run the shards ($1.45/GB-mo -- the price floor, that's the least it would cost at 100% utilization)
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Mongo's disk-based, but storage wasn't the problem...
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Switched to Redis, designed their own sharding system (you guess it -- it was painful) "Redis ring"
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DynamoDB... can only change up or down a few times today
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$0.28/GB-mo
- Ad serving
- Have to respond quickly (40ms) about whether they will serve an ad
- If you need the service, DynamoDB makes it cheaper to do instead of doing the infrastructure yourself
- Lots of performance and redundancy problems are solved for you (built for high availability and ultra-fast responses)
- Sounds like you can back up to S3? Maybe Glacier? Unsure
Things to think about for your app:
- Storage
- IOPS
Things not to think about for your app:
- Sharding -- nice if it's taken care of for you
Not part of the talk:
- Not much info about how DynamoDB actually works (developer centric)
- It's a different implementation than Dynamo. Only proprietary implementations of the API.
- To build against it, you'll have to use Amazon's implementation, but they offer a desktop version (Java)
- Ruby SDK, not aware of a generic wrapper for KV stores that supports it
- Migration strategy to/from DynamoDB is unclear to me
- Related: SimpleDB (also Amazon proprietary), MongoDB, Couchbase, Cassandra, Riak
