Memory Planning

• If I plan to store X documents with Y KB in size - what's the formula for memory requirements?

• Search engines including ElasticSearch perform the best when data and index are cached in memory

• How many aggregate queries vs. filtered queries vs. scan queries would you run?

• How many request per second of each type are you planning to support?

• How often will you be taking full snapshots and incremental snapshots?

• How much memory is enough memory?

• ElasticSearch is not a database per ce, hence it 'does not look before it leaps...'

• Approach recommended by Elastic: "start out with more memory than you need and scale down to find the sweet spot"

• Do not enable memory disk swap - it is deadly for ElasticSearch performance

• Swap file might need to be disabled for other NoSql as well e.g.:Cassandra