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From Colin <co...@clark.ws>
Subject Re: Tune cache MB settings per table.
Date Mon, 02 Jun 2014 00:05:59 GMT
Your data model will most likely be the far most important component of your migration.  Get
that right, and the rest is easy.

--
Colin Clark 
+1-320-221-9531
 

> On Jun 1, 2014, at 7:01 PM, Kevin Burton <burton@spinn3r.com> wrote:
> 
> Good question. still migrating.. but we don't want to paint ourselves into a corner.
> 
> There's an interesting line between premature optimization and painting yourself into
a corner ;)
> 
> Best to get it right in between both extremes.
> 
> 
>> On Sun, Jun 1, 2014 at 4:30 PM, Colin <colpclark@gmail.com> wrote:
>> 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.
> 
> 
> 
> -- 
> 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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