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From stanlukya...@gmail.com
Subject Re: Do we require to set MaxDirectMemorySize JVM parameter?
Date Mon, 24 Dec 2018 09:10:36 GMT
We’re actually looking into off-heap memory usage of ignite now, specifically into the MaxDirectMemorySize
needed.

So far it seems that MaxDirectMemorySize=256m should work. It may need to be larger if you
use non-default walSegmentSize.

Not limiting the direct memory size may result in excessive allocation, more work for garbage
collector and even OOM.

My early recommendation (note that the investigation is still in progress) would be to set
the parameter to 256mb and increase it if you hit “OOME: direct memory”. We’ll have
it published on readme.io when the testing is done.

Stan 

> On 24 Dec 2018, at 11:42, Павлухин Иван <vololo100@gmail.com> wrote:
> 
> Hi summasumma,
> 
>> Means, i should have minimum 16 Gb of RAM (8 dataregion+ 8 directmem) for
>> Ignite to run properly i guess.
> 
> Not quite. Actually, I am not aware that Ignite requires some special
> tuning of MaxDirectMemorySize. If direct memory causes OOME then the
> exception message usually points it out (e.g. "Direct buffer memory").
> Check if it is your case.
> 
> Indeed you should be careful when configure DataRegion.maxSize because
> OOME is a real problem and you will get it if put more data into
> Ignite than specified limit. One should carefully plan how many data
> is going to be stored into Ignite when in-memory mode is used. Also,
> it is possible to use Ignite native persistence or configure swap to
> overcome OOME [1]. Also page about capacity planning might be useful
> here [2].
> 
> [1] https://apacheignite.readme.io/docs/durable-memory
> [2] https://apacheignite.readme.io/docs/capacity-planning
> 
> пн, 24 дек. 2018 г. в 09:53, summasumma <bytestreams@gmail.com>:
>> 
>> Thanks Ivan.
>> 
>> This means having both configuration as follows:
>> xml        --> <property name="maxSize" value="#{8L * 1024 * 1024 * 1024}"/>
>> jvmption --> "-XX:MaxDirectMemorySize=8g"
>> 
>> Means, i should have minimum 16 Gb of RAM (8 dataregion+ 8 directmem) for
>> Ignite to run properly i guess.
>> 
>> In my current setup i have 16GB of total ram and given 12GB=maxSize
>> Dataregion and jvmoption as '-XX:MaxDirectMemorySize=8g'. And this is
>> crashing Ignite with OOME after a while (though not immediatly) when i try
>> to do a performance testing of Update operation. so this means either i
>> should increase the RAM or decrease the XX:MaxDirectMemorySize to 4g ?
>> 
>> Please clarify
>> 
>> Thanks
>> ...summa
>> 
>> 
>> 
>> --
>> Sent from: http://apache-ignite-users.70518.x6.nabble.com/
> 
> 
> 
> -- 
> Best regards,
> Ivan Pavlukhin

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