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From Paul Pak <>
Subject Re: Nodes frozen in GC
Date Tue, 08 Mar 2011 18:43:21 GMT
Hi Ruslan,

Is it possible for you to tell us the details on what you have done
which measurably helped your situation, so we can start a "best
practices" doc on growing cassandra systems? 

So far, I see that under load, cassandra is rarely "ready" to take heavy
load in it's default configuration and a number of steps need to be done
with the configuration of cassandra for proper sizing of memtables,
flushing, jvm.  Unfortunately, it's very difficult to gauge what the
proper or appropriate settings are for a given workload.

It would be helpful if you could share, what happened in the default
config, what steps you did that helped the situation, h Tow much each
step helped your situation.  That way we can start a checklist of things
to address as we grow in load.


On 3/8/2011 5:15 AM, ruslan usifov wrote:
> 2011/3/8 Paul Pak < <>>
>     Hi Ruslan,
>     It looks like Jonathan and Stu have already been working to reduce
>     garbage collection on v.8  The ticket is at
>     Jonathan, is there any way to apply the patch to .73 and have
>     ruslan test it to see if it fixes his issue with Garbage
>     collection?  Given the fact that he's already got a test case, it
>     seems like a reasonable thing to do (with the caveat that he is a
>     guinea pig for new code which may not be fully tested yet :) .
> Thanks Paul for information, it very informative. But how this work at
> others. I see that situation stay better when i increase heap size to
> 7GB, but nodes still frozen truth not so frequent as before, but
> still, also but I don;t probe this i think that setting -Xmn to
> something bigger then 800M may give benefit
> (
> |
> | 

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