[lustre-discuss] OST partition sizes

[Scott Nolin]

Ah, I used 256K xfersize for all my tests. 1MB would probably be a 
better test.

Scott

On 4/29/2015 11:38 AM, Alexander I Kulyavtsev wrote:
> ior/bin/IOR.mpiio.mvapich2-2.0b -h
>
> -t N  transferSize -- size of transfer in bytes (e.g.: 8, 4k, 2m, 1g)
>
> IOR reports it in the log :
>
> Command line used:
> /home/aik/lustre/benchmark/git/ior/bin/IOR.mpiio.mvapich2-2.0b -v -a
> MPIIO -i5 -g -e -w -r -b 16g -C -t 8k -o
> /mnt/lfs/admin/iotest/ior/stripe_2/ior-testfile.ssf
> ...
> Summary:
>
>          api                = MPIIO (version=3, subversion=0)
>          test filename      =
> /mnt/lfs/admin/iotest/ior/stripe_2/ior-testfile.ssf
>          access             = single-shared-file, independent
>          pattern            = segmented (1 segment)
>          ordering in a file = sequential offsets
>          ordering inter file=constant task offsets = 1
>          clients            = 32 (8 per node)
>          repetitions        = 5
>          xfersize           = 8192 bytes
>          blocksize          = 16 GiB
>          aggregate filesize = 512 GiB
>
> Here we have xfersize 8k, each client of 32 writes 16GB, so the
> aggregate file size is 512GB.
>
> I would expect records size to be ~1MB for our workloads.
>
> Best regards, Alex.
>
> On Apr 29, 2015, at 11:07 AM, Scott Nolin <scott.nolin at ssec.wisc.edu
> <mailto:scott.nolin at ssec.wisc.edu>> wrote:
>
>> Ok I looked up my notes.
>>
>> I'm not really sure what you mean by record size. I assumed when I do
>> a file per process the block size = file size. And that's what I see
>> dropped on the filesystem.
>>
>> I did -F -b <size>
>>
>> With block sizes 1MB, 20MB, 100MB, 200MB, 500MB
>>
>> 2, 4, 8, 16 threads on 1 to 4 clients.
>>
>> I assumed 2 threads on 1 client looks a lot like a client writing or
>> reading 2 files. I didn't bother looking at 1 thread.
>>
>> Later I just started doing 100MB tests since it's a very common file
>> size for us. Plus I didn't see real big difference once size gets
>> bigger than that.
>>
>> Scott
>>
>>
>> On 4/29/2015 10:24 AM, Alexander I Kulyavtsev wrote:
>>> What range of record sizes did you use for IOR? This is more important
>>> than file size.
>>> 100MB is small, overall data size (# of files) shall be twice as memory.
>>> I ran series of test for small record size for raidz2 10+2; will re-run
>>> some tests after upgrading to 0.6.4.1 .
>>>
>>> Single file performance differs substantially from file per process.
>>>
>>> Alex.
>>>
>>> On Apr 29, 2015, at 9:38 AM, Scott Nolin <scott.nolin at ssec.wisc.edu
>>> <mailto:scott.nolin at ssec.wisc.edu>
>>> <mailto:scott.nolin at ssec.wisc.edu>> wrote:
>>>
>>>> I used IOR, singlefile, 100MB files. That's the most important
>>>> workload for us. I tried several different file sizes, but 100MB
>>>> seemed a reasonable compromise for what I see the most. We rarely or
>>>> never do file striping.
>>>>
>>>> I remember I did see a difference between 10+2 and 8+2. Especially at
>>>> smaller numbers of clients and threads, the 8+2 performance numbers
>>>> were more consistent, made a smoother curve. 10+2 with not a lot of
>>>> threads the performance was more variable.
>>>
>>
>>
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>


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