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From Colin <colpcl...@gmail.com>
Subject Re: Tune cache MB settings per table.
Date Sun, 01 Jun 2014 23:30:57 GMT
Have you been unable to achieve your SLA's using Cassandra out of the box so far?

Based upon my experience, trying to tune Cassandra before the app is done and without simulating
real world load patterns, you might actually be doing yourself a disservice.

--
Colin
320-221-9531


> On Jun 1, 2014, at 6:08 PM, Kevin Burton <burton@spinn3r.com> wrote:
> 
> Not in our experience… We've been using fadvise don't need to purge pages that aren't
necessary any longer.
> 
> Of course YMMV based on your usage.  I tend to like to control everything explicitly
instead of having magic.
> 
> That's worked out very well for us in the past so it would be nice to still have this
on cassandra.
> 
> 
>> On Sun, Jun 1, 2014 at 12:53 PM, Colin <colin@clark.ws> wrote:
>> The OS should handle this really well as long as your on v3 linux kernel....  
>> 
>> --
>> Colin Clark 
>> +1-320-221-9531
>>  
>> 
>>> On Jun 1, 2014, at 2:49 PM, Kevin Burton <burton@spinn3r.com> wrote:
>>> 
>>> It's possible to set caching to:
>>> 
>>> all, keys_only, rows_only, or none
>>> 
>>> .. for a given table.
>>> 
>>> But we have one table which is MASSIVE and we only need the most recent 4-8 hours
in memory.  
>>> 
>>> Anything older than that can go to disk as the queries there are very rare.
>>> 
>>> … but I don't think cassandra can do this (which is a shame).
>>> 
>>> Another option is to partition our tables per hour… then tell the older tables
to cache 'none'… 
>>> 
>>> I hate this option though.  A smarter mechanism would be to have a compaction
strategy that created an SSTable for every hour and then had custom caching settings for that
table.
>>> 
>>> The additional upside for this is that TTLs would just drop the older data in
the compactor.. 
>>> 
>>> -- 
>>> Founder/CEO Spinn3r.com
>>> Location: San Francisco, CA
>>> Skype: burtonator
>>> blog: http://burtonator.wordpress.com
>>> … or check out my Google+ profile
>>> 
>>> War is peace. Freedom is slavery. Ignorance is strength. Corporations are people.
> 
> 
> 
> -- 
> Founder/CEO Spinn3r.com
> Location: San Francisco, CA
> Skype: burtonator
> blog: http://burtonator.wordpress.com
> … or check out my Google+ profile
> 
> War is peace. Freedom is slavery. Ignorance is strength. Corporations are people.

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