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From DV <vind...@gmail.com>
Subject Re: KahaDB disk utilization
Date Wed, 26 Sep 2012 17:23:03 GMT
Though I really like the idea of mKahaDB, it's unusable to us right
now because of the bug described in AMQ-3841 - we frequently encounter
it with AMQ 5.6 and the fix isn't due until 5.7 is out :/

- DV

On Wed, Sep 26, 2012 at 2:54 AM, Claus Ibsen <claus.ibsen@gmail.com> wrote:
> 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
> -----------------
> Red Hat, Inc.
> FuseSource is now part of Red Hat
> Email: cibsen@redhat.com
> Web: http://fusesource.com
> Twitter: davsclaus
> Blog: http://davsclaus.com
> Author of Camel in Action: http://www.manning.com/ibsen



-- 
Best regards, Dmitriy V.

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