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From Aaron Morton <>
Subject Re: memory consuption
Date Fri, 18 Feb 2011 00:19:10 GMT
Change your disk_access_mode standard to remove the virtual memory usage. 

Some info on JNA


On 18 Feb, 2011,at 09:00 AM, Aaron Morton <> wrote:

What are you using for disk_access_mode ?
Have you tried reducing the JVM head size?
Have you added the Jna.jar file to lib/ ? This will allow Cassandra to lock the JVM memory.


On 17/02/2011, at 9:20 PM, ruslan usifov <> wrote:

2011/2/16 Aaron Morton <>
JVM heap memory is controlled by the settings in conf/

Memory mapped files will use additional virtual memory, is controlled in conf/Cassandra.yaml

And??? JVM memory heap in cassandra 0.7 is by default half of memory is system in my case
4GB, here is a part of

    case "`uname`" in
            system_memory_in_mb=`free -m | awk '/Mem:/ {print $2}'`
            MAX_HEAP_SIZE=$((system_memory_in_mb / 2))M
            return 0
            system_memory_in_bytes=`sysctl hw.physmem | awk '{print $2}'`
            MAX_HEAP_SIZE=$((system_memory_in_bytes / 1024 / 1024 / 2))M
            return 0
            return 1

I set all this options by default. All my nodes have 8GB of memory. And i affraid that after
some time all my nodes goes to hard swap, and only reboot help them :-(((

PS: as i understand that down sometime of cassandra is normal?

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