Issue with verify and Mix read/writes

Issue with verify and Mix read/writes

[Suresh Dhanarajan]

Hi Jens,

I am using the verify option with mix read and write case.
When verify option is I am seeing that the results are not reflecting
the actual percentage given in the jobfile.
When i don't use verify option the results are exactly as per the
percentage given in the jobfile.

Please fin the result for various cases with and without verify option,

withverify sequential :-
Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
2988;2436;594;1256
10240;6565;1603;1597
===================
wthoutverify sequential :-
Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
3124;2460;600;1300
7116;5605;1368;1300
===================

random with verify
Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
3088;431;105;7322
10240;1363;332;7693
===============

random without verify
Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
3076;430;105;7311
7164;1003;244;7311

I used 70% read and 30% write option.
Is it that when verify is used the mix percentage wont be honored?
I had mentioned size has 10mb but when verify is used even that is not
getting honored.
Is there a way to make this case to honor the percentage set in the job file?

Thanks,
Suresh.D

Re: Issue with verify and Mix read/writes

[Jens Axboe]

On 04/19/2012 12:14 AM, Suresh Dhanarajan wrote:
> Hi Jens,
> 
> I am using the verify option with mix read and write case.
> When verify option is I am seeing that the results are not reflecting
> the actual percentage given in the jobfile.
> When i don't use verify option the results are exactly as per the
> percentage given in the jobfile.
> 
> Please fin the result for various cases with and without verify option,
> 
> withverify sequential :-
> Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
> 2988;2436;594;1256
> 10240;6565;1603;1597
> ===================
> wthoutverify sequential :-
> Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
> 3124;2460;600;1300
> 7116;5605;1368;1300
> ===================
> 
> random with verify
> Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
> 3088;431;105;7322
> 10240;1363;332;7693
> ===============
> 
> random without verify
> Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec)
> 3076;430;105;7311
> 7164;1003;244;7311
> 
> I used 70% read and 30% write option.
> Is it that when verify is used the mix percentage wont be honored?
> I had mentioned size has 10mb but when verify is used even that is not
> getting honored.
> Is there a way to make this case to honor the percentage set in the job file?

The reads that are done to verify a written block are not accounted in
the read/write mix ratio. So that is why you see more reads than you
asked for.

-- 
Jens Axboe