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From srmore <comom...@gmail.com>
Subject Re: Cassandra Heap Size for data more than 1 TB
Date Wed, 02 Oct 2013 12:25:39 GMT
The version of Cassandra I am using is 1.0.11, we are migrating to 1.2.X
though. We had tuned bloom filters (0.1) and AFAIK making it lower than
this won't matter.

Thanks !


On Tue, Oct 1, 2013 at 11:54 PM, Mohit Anchlia <mohitanchlia@gmail.com>wrote:

> Which Cassandra version are you on? Essentially heap size is function of
> number of keys/metadata. In Cassandra 1.2 lot of the metadata like bloom
> filters were moved off heap.
>
>
> On Tue, Oct 1, 2013 at 9:34 PM, srmore <comomore@gmail.com> wrote:
>
>> Does anyone know what would roughly be the heap size for cassandra with
>> 1TB of data ? We started with about 200 G and now on one of the nodes we
>> are already on 1 TB. We were using 8G of heap and that served us well up
>> until we reached 700 G where we started seeing failures and nodes flipping.
>>
>> With 1 TB of data the node refuses to come back due to lack of memory.
>> needless to say repairs and compactions takes a lot of time. We upped the
>> heap from 8 G to 12 G and suddenly everything started moving rapidly i.e.
>> the repair tasks and the compaction tasks. But soon (in about 9-10 hrs) we
>> started seeing the same symptoms as we were seeing with 8 G.
>>
>> So my question is how do I determine what is the optimal size of heap for
>> data around 1 TB ?
>>
>> Following are some of my JVM settings
>>
>> -Xms8G
>> -Xmx8G
>> -Xmn800m
>> -XX:NewSize=1200M
>> XX:MaxTenuringThreshold=2
>> -XX:SurvivorRatio=4
>>
>> Thanks !
>>
>
>

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