Tried, dont work that way. hence the issue.
On Thu, Jul 13, 2017 at 2:01 PM, Andrey Kuzmin
<andrey.v.kuzmin@xxxxxxxxx> wrote:
>
>
> On Thu, Jul 13, 2017, 23:57 abhishek koundal <akoundal@xxxxxxxxx> wrote:
>>
>> Yes that is correct.
>> So e.g. if you have RND_RD b/w 45MBps and had 10%SEQ_WR 90%RND_RD the
>> write throughput will be:
>> =10/100 *45MBs = ~4.5MB/s
>>
>> Now if you try to cap the write throughput (rate =5m) to this in
>> Linux, the RND_RD also gets impacted and wont run to its full
>> potential.
>>
>> In StorScor reads thread will not get capped and only writes thread
>> will be capped, hence deliver the expected results.
>
>
> Just off the top of my head, won't you get the same in fio by setting up two
> jobs to run in parallel, first doing capped sequential writes, and another
> one doing unconstrained random reads?
>
> Regards,
> Andrey
>>
>>
>> On Thu, Jul 13, 2017 at 1:33 PM, Sitsofe Wheeler <sitsofe@xxxxxxxxx>
>> wrote:
>> > Hey,
>> >
>> > My Perl is a bit rusty but look at how the write throughput is
>> > calculated:
>> >
>> > # Run again, this time with an aggressor process injecting
>> > # writes in the background. The aggressor is rate-limited
>> > # to a fraction of the baseline read throughput.
>> > foreach my $write_workload ( @write_workloads )
>> > {
>> > my ($write_pattern, $write_pct) = @$write_workload;
>> >
>> > my $write_tput_KBps =
>> > int ( ( $write_pct / 100 ) * $read_tput_KBps );
>> >
>> > So it is accounting for the fact that the write throughput will be
>> > limited to a percentage of the read throughput.
>> >
>> > On 13 July 2017 at 20:02, abhishek koundal <akoundal@xxxxxxxxx> wrote:
>> >> Hi,
>> >> The main thing that i am trying to do is to model the storScor in
>> >> linux enviornment
>> >>
>> >> (https://github.com/Microsoft/StorScore/blob/master/recipes/write_impact_check.rcp).
>> >> So there you can control the rate of the of the writes as per the %
>> >> that is required. While running that on windows i can see that i can
>> >> have different BS and rate defined for the runs achieving expected
>> >> output.
>> >>
>> >> In the above mentioned case the RND_RD will be unconstrained (i.e.
>> >> full BW they can achieve) but writes will be slowed to x% of RND_RD.
>> >> In fio when
>> >> e.g.
>> >> SEQ_WR 10% and RND_RD 90%, with seq_wr rate capped at 10% of rnd rd
>> >> (if rnd_rd was 40m)
>> >> [SEQ_WR]
>> >> rate=4m
>> >> bs=128K
>> >> rw=write
>> >> flow=9
>> >> [RND_RD]
>> >> rate=40m
>> >> bs=4k
>> >> rw=randread
>> >> flow=-1
>> >> When i run this the output that comes back shows that SEQ_WR b/w is
>> >> capped ~ 4m but RND_RD also gets severely hit for the IOPS+BW as it
>> >> tried to put the total BW under <45m>. I want that RND_RD doesn't need
>> >> to be capped and should run to it closest potential like I am see in
>> >> storScor.
>> >> Really appreciate for the support and helping me understand the
>> >> limitations.
>> >
>> > --
>> > Sitsofe | http://sucs.org/~sits/
>>
>>
>>
>> --
>> Life is too short for silly things so invest your time in some
>> productive outputs!!
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>
> --
>
> Regards,
> Andrey
--
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