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From Edward Capriolo <edlinuxg...@gmail.com>
Subject Re: SSTable size versus read performance
Date Thu, 16 May 2013 19:48:42 GMT
I was going to say something similar I feel like the SSD drives read much
"more" then the standard drive. Read Ahead/arge sectors could and probably
does explain it.


On Thu, May 16, 2013 at 3:43 PM, Bryan Talbot <btalbot@aeriagames.com>wrote:

> 512 sectors for read-ahead.  Are your new fancy SSD drives using large
> sectors?  If your read-ahead is really reading 512 x 4KB per random IO,
> then that 2 MB per read seems like a lot of extra overhead.
>
> -Bryan
>
>
>
>
> On Thu, May 16, 2013 at 12:35 PM, Keith Wright <kwright@nanigans.com>wrote:
>
>> We actually have it set to 512.  I have tried decreasing my SSTable size
>> to 5 MB and changing the chunk size to 8 kb
>>
>> From: Igor <igor@4friends.od.ua>
>> Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org>
>> Date: Thursday, May 16, 2013 1:55 PM
>>
>> To: "user@cassandra.apache.org" <user@cassandra.apache.org>
>> Subject: Re: SSTable size versus read performance
>>
>> My 5 cents: I'd check blockdev --getra for data drives - too high values
>> for readahead (default to 256 for debian) can hurt read performance.
>>
>>

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