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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Cassandra consume large memory
Date Mon, 18 Jul 2011 16:05:41 GMT
No, the point is that it's the same memory that would be cached anyway
if you were using non-mmap'd I/O.

This will be more obvious once you have say 10x more data (and SHR)
than you have ram (and RES).

On Mon, Jul 18, 2011 at 10:27 AM, JKnight JKnight <beuknight@gmail.com> wrote:
> Thank for your response.
> Can we reduce that value? Memory is used just 600M but the process occupy
> 3.2G. Too waste.
>
> On Mon, Jul 18, 2011 at 6:53 PM, Jonathan Ellis <jbellis@gmail.com> wrote:
>>
>> That means that the mmaped files are indeed resident at the moment.
>>
>> On Mon, Jul 18, 2011 at 1:51 AM, JKnight JKnight <beuknight@gmail.com>
>> wrote:
>> > Thank for your response.
>> > Do you talk about virtual memory (column VIRT show in top command)?
>> > But I mention about column RES. In my case, VIRT is 61.8G, RES is 3.2G
>> > and
>> > SHR is 1.2G.
>> > JMX show Memory Usage:
>> > Used : 600MB, Commit 2.1G, Max: 2.1G
>> > On Mon, Jul 18, 2011 at 11:59 AM, Jonathan Ellis <jbellis@gmail.com>
>> > wrote:
>> >>
>> >> http://wiki.apache.org/cassandra/FAQ#mmap
>> >>
>> >> On Sun, Jul 17, 2011 at 11:54 PM, JKnight JKnight <beuknight@gmail.com>
>> >> wrote:
>> >> > Dear all,
>> >> > I use JMX to monitor Cassandra server.
>> >> > Heap Memory Usage show:
>> >> > Used : 600MB, Commit 2.1G, Max: 2.1G
>> >> > But htop show Cassandra process consume 3.1G.
>> >> > Could you tell me why Cassandra occupy memory very large than in
>> >> > used?
>> >> > Thank a lot for support.
>> >> > --
>> >> > Best regards,
>> >> > JKnight
>> >> >
>> >>
>> >>
>> >>
>> >> --
>> >> Jonathan Ellis
>> >> Project Chair, Apache Cassandra
>> >> co-founder of DataStax, the source for professional Cassandra support
>> >> http://www.datastax.com
>> >
>> >
>> >
>> > --
>> > Best regards,
>> > JKnight
>> >
>>
>>
>>
>> --
>> Jonathan Ellis
>> Project Chair, Apache Cassandra
>> co-founder of DataStax, the source for professional Cassandra support
>> http://www.datastax.com
>
>
>
> --
> Best regards,
> JKnight
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com

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