A short update, I just tried to run larger mdtest (I still calibrate). For mdt easy, the
create takes 4 minutes and for the hard takes 4.5 minutes (I am getting close). I do
create 2 million files. This moment still has not finished the command find and it takes
20 minutes. Total execution of the benchmark without having calibrated IOR to 5 minutes,
is almost 46 minutes and counting till the command "find" finishes. All the IOR
except the hard write, took less than 2 minutes and the hard write took 7.7 minutes. We
miss the mix workload also. I use 1000 compute nodes with 2 MPI processes per node. I
have time limit 1 hour, so I am afraid that it could be killed due to time limit.
George Markomanolis, PhD
KAUST Supercomputing Laboratory (KSL)
King Abdullah University of Science & Technology
Al Khawarizmi Bldg. (1) Room 0123
Kingdom of Saudi Arabia
Mob: +966 56 325 9012
Office: +966 12 808 0393
From: John Bent <John.Bent(a)seagategov.com>
Sent: Friday, June 30, 2017 3:27 AM
To: Andreas Dilger
Cc: Georgios Markomanolis; Julian Kunkel; io-500(a)vi4io.org
Subject: Re: [IO-500] ISC BOF report
On Jun 29, 2017, at 2:11 PM, Andreas Dilger <adilger(a)dilger.ca>
On Jun 29, 2017, at 5:58 PM, John Bent <John.Bent(a)seagategov.com> wrote:
>> On Jun 29, 2017, at 1:52 PM, Andreas Dilger <adilger(a)dilger.ca> wrote:
>>>> On Jun 29, 2017, at 5:47 PM, John Bent <John.Bent(a)seagategov.com>
>>>> On Jun 29, 2017, at 1:35 PM, Andreas Dilger <adilger(a)dilger.ca>
>>>> That means the result needs to be in "files per second"
>>> Absolutely. It will be just a fifth iops number to combine with the other 4
IOPs numbers (mdtest create easy/hard and mdtest stat easy/hard) using geo mean.
>>> Figure out the number of files created by the four produce phases: n. Then
divide that by wall-clock for the find command: w. Then the 'find' IOPs is n/w.
>>> My concern is that it will be so slow that people will give up and not run
>> I don't see why that would be true? For Lustre at least, readdir() and
stat() are about 2x as fast as creating files.
> Even if you create across 10,000 nodes and then readdir from just 1?
Hmm, good point. I was thinking about parallel stat, but it isn't orders of
magnitude slower. George mentioned the find command took 3-4 minutes, which isn't
slower than the 5-minute create phase...
I don't think George has done a 5-min create phase yet. He's just getting
the scripts working still.
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