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From Claus Ibsen <claus.ib...@gmail.com>
Subject Re: KahaDB disk utilization
Date Wed, 26 Sep 2012 09:54:33 GMT
Hi



On Wed, Sep 26, 2012 at 5:14 AM, DV <vindimy@gmail.com> wrote:
> Are you absolutely certain that there are exactly 10M messages on the
> broker? I've seen a huge KahaDB store with only a few messages in the
> queue because the earlier published messages weren't de-queued
> ("stuck" messages).
>

Yes and you can use multi KahaDB to distribute destinations in different files
which can help reduce disk space. You can read a bit about it here:
http://activemq.apache.org/kahadb.html


> On the other hand, maybe KahaDB sacrifices space for performance, kind
> of like MongoDB does.
>
> - DV
>
> On Wed, Sep 19, 2012 at 8:29 AM, Oleg Dulin <oleg.dulin@gmail.com> wrote:
>> Dear Distinguished Colleagues:
>>
>> I've been trying to understand something.
>>
>> My queues take Java object messages. Serialized into bytes, each Java object
>> is about 1.5K on average.
>>
>> When I have a backlog of 10 million objects on one of the queues, the disk
>> utilization of kahadb is around 50gigs. But this math here:
>>
>> groovy:000> 1500*10000000/1024/1024/1024;
>> ===> 1.9698386192
>>
>> means that 10M objects should only take up less than 2gigs.
>>
>> Even if I had 3 queues going with the same objects, the total would be 6gigs
>> max. So why the disk utilization overhead ? How much does a single JMS
>> message need ?
>>
>>
>> --
>> Regards,
>> Oleg Dulin
>> NYC Java Big Data Engineer
>> http://www.olegdulin.com/
>>
>>
>
>
>
> --
> Best regards, Dmitriy V.



-- 
Claus Ibsen
-----------------
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Email: cibsen@redhat.com
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Author of Camel in Action: http://www.manning.com/ibsen

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