Re: fio usage question

[David Nellans <david@nellans.org>]

you just need to adequately keep the sectors being written by each job 
segregated.
filenames, blkdev ranges, read only jobs - a variety of ways you could 
keep them from
trouncing on each other depending what your job is doing.

if you don't then you'll have a race where one process can change the 
data on disk
before the other job has verified,  leading to false verify failures.

On 08/18/2014 10:46 AM, John OCallaghan wrote:
>
> Thanks David, am not using verify but am curious how this can get affected.
>
> Would it be that job configs that use the same file names would clobber
> one anothers data on disk? I could see how that would be an issue for
> multi process fio instances alright.
>
>
>
>
> On 18/08/14 16:38, David Nellans wrote:
>> On 08/18/2014 10:03 AM, John OCallaghan wrote:
>>> Hi All
>>>
>>> A question on usage of fio. I would like to be able to spin up more than
>>> one fio instance running on the same platform concurrently.
>>>
>>> For example, I would like to run one fio instance in time_based mode
>>> doing some stuff. And after a fixed period of time then start a non-time
>>> based fio instance doing some other stuff.
>>>
>>> I have tried it out and to my untrained eyes it looks like its going OK.
>>> But I'd love to hear from others with more experience in this area. Is
>>> this something that is recommended?
>>>
>>> Will my data skew in some way because fio expects there to be only one
>>> instance of itself playing at any one time?
>>>
>>> Any advice would be much appreciated!
>>>
>> Different processes shouldn't run into any issues unless you're doing a
>> job with
>> verification in which case you'll end up with verify errors due to jobs
>> overwriting each
>> other's data.
>>
>> Unless you want to use multiple processes for some reason versus jobs
>> inside a single
>> process - you can delay one of your multiple jobs starting using the
>> startdelay=N
>> parameter in the jobfile.
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