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From Nikolay KŠ¾vshov <>
Subject OOM on heavy write load
Date Fri, 22 Apr 2011 13:00:53 GMT
I am using Cassandra 0.7.0 with following settings

binary_memtable_throughput_in_mb: 64
in_memory_compaction_limit_in_mb: 64
keys_cached 1 million
rows_cached 0

RAM for Cassandra 2 GB

I run very simple test

1 Node with 4 HDDs (1 HDD - commitlog and caches, 3 HDDs - data)
1 KS => 1 CF => 1 Column

I insert data (random key 64 bytes + value 64 bytes) at a maximum possible speed, trying to
hit disk i/o, calculate speed and make sure Cassandra stays alive. It doesn't, unfortunately.
After several hundreds millions of inserts Cassandra always does down by OOM. Getting it up
again doesn't help - after inserting some new data it goes down again. By this time Cassandra
goes to swap and has a lot of tasks pending. I am not inserting anything now and tasks sloooowly
disappear, but it will take her weeks to do all of them.

compaction type: Minor
column family: Standard1
bytes compacted: 3661003227
bytes total in progress: 4176296448
pending tasks: 630

So, what am I (or Cassandra) doing wrong ? I dont want to get Cassandra crashed without means
of repair on heavy load circumstances.

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