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From Idrén, Johan <>
Subject memtable mem usage off by 10?
Date Wed, 04 Jun 2014 09:49:30 GMT

I'm seeing some strange behavior of the memtables, both in 1.2.13 and 2.0.7, basically it
looks like it's using 10x less memory than it should based on the documentation and options.

10GB heap for both clusters.

1.2.x should use 1/3 of the heap for memtables, but it uses max ~300mb before flushing

2.0.7, same but 1/4 and ~250mb

In the 2.0.7 cluster I set the memtable_total_space_in_mb to 4096, which then allowed cassandra
to use up to ~400mb for memtables...

I'm now running with 20480 for memtable_total_space_in_mb and cassandra is using ~2GB for

Soo, off by 10 somewhere? Has anyone else seen this? Can't find a JIRA for any bug connected
to this.

java 1.7.0_55, JNA 4.1.0 (for the 2.0 cluster)



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