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From: Thomas Schneider <74cmonty@gmail.com>
To: Vincent Fu <vincentfu@gmail.com>, fio@vger.kernel.org
Subject: Re: Using fio with adjusted parameters for use case "DB"
Date: Wed, 8 Mar 2023 14:46:41 +0100	[thread overview]
Message-ID: <0f93974c-e374-cae4-f165-d81583c5441f@gmail.com> (raw)
In-Reply-To: <c048da7e-ab6d-0209-52b9-5d4262658ab0@gmail.com>

Hello,

thanks for your reply.

I have discussed with DB developers which values should be used for
- iodepth and
- numjobs

With regards to iodepth I was told that a max. value could be defined in 
DB's global ini; the default is 512.
This means the DB could use this queue depth as max. but certainly no as 
average.

Question:
 From your experience, does it make sense to run IO benchmark with 
iodepth=512?


THX



Am 07.03.2023 um 16:22 schrieb Vincent Fu:
> On 3/7/23 09:30, Thomas Schneider wrote:
>> Hello,
>>
>> I want to benchmark different storage devices with an I/O workload 
>> generated by the "real" application: DB.
>>
>> A typcial command could be:
>> fio --name=random-writers --ioengine=libaio --iodepth=4 
>> --rw=randwrite --bs=1024 --direct=1 --size=64m --numjobs=2 runtime=120s
>>
>> The question is regarding parameters size and runtime:
>> - What value should be used for size? Should this be the same as 
>> allocated disk space by DB data files? Or just a (reasonable) portion 
>> of this? DB data files could be up to xTB.
>> - Is it advisable to use runtime? If yes, would this somehow 
>> contradict to size, means if I use a larger size, then runtime is 
>> obviously longer.
>>
>
> The documentation for runtime is here:
>
> https://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-runtime
>
> Fio will write within the LBAs bounded by offset and size and stop 
> when it has touched all the LBAs or when runtime is attained. Run some 
> experiments with --debug=io to better understand fio's behavior.
>
> Also take a look at the example job files for help:
>
> https://github.com/axboe/fio/tree/master/examples
>
> Vincent
>

next prev parent reply	other threads:[~2023-03-08 13:47 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-07 14:30 Using fio with adjusted parameters for use case "DB" Thomas Schneider
2023-03-07 15:22 ` Vincent Fu
2023-03-08 13:46   ` Thomas Schneider [this message]
  -- strict thread matches above, loose matches on Subject: below --
2023-03-02  9:49 74cmonty

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