[CentOS] Benchmark Disk IO

On 05/19/2010 06:14 AM, John Doe wrote:
> From: Matt Keating<keatster at gmail.com>
>    
>>> I don't usually use iozone (I usually use bonnie++) so take this with
>>> a grain of salt, but those speed look suspiciously like cache speeds.
>>> Bump the size (-s parameter) up to twice your real RAM size.
>>>        
>> Will give that a try - 16gb file incoming
>>      
> Or maybe do a:
>    sync; echo 3>  /proc/sys/vm/drop_caches
> between the 2 tests...?
>    
It wouldn't help. The problem is the tests were using file sizes small 
enough to easily fit completely into the system caches. So you end up 
benchmarking the performance of the I/O system caches - not the drives 
themselves.

-- 
Benjamin Franz