In general, I'd expect metadata operations to be the main scalability
limitation for "distributed storage" solutions (like Lustre, but also
like DPM and dCache), assuming a good distribution of data across the
storage.
It might be more useful to try to test the number of concurrent
metadata reads (srm-ls?) and writes (changing file ownership?) that
the system supports...
Sam
On 8 May 2012 11:17, Alex Martin <[log in to unmask]> wrote:
> On Tuesday 08 May 2012 10:21:35 David Wallom wrote:
>> Hi Alex,
>>
>> Thanks, will you be doing I/O perf measurements as part of the acceptance
>> testing?
>
> Its actually quite difficult to measure the total I/O performance of the
> whole cluster. What we did, before we upgraded all the network to 10Gb+,
> was to measure the performance of a "brick" consisting of 6 storage
> servers and 12 cpu boxes and upto 4 threads/node on one switch. This gave
> us ~1.2 GB/s matching the 10 Gb switch uplinks we had at the time. Now
> that we have 10 Gb everywhere I would expect the equivalent "brick"
> performance to be only a bit better, but we can agregate more together
> in the rack switches and the trunking to the z9000's won't be a limitation.
>
>
>
>
>> Does anyone know of any limits inside any of the solutions for
>> the catalogues etc?
>>
>> David
>>
>> >Hi David,
>> >
>> > We are fairly confident that our current
>> >
>> >Lustre/Storm
>> >setup (which will shortly be ~1.8 PB) could be scaled a factor of
>> >~10,
>> >without big problems now that we upgraded our switches. We will probably
>> >be
>> >able to quantify this a bit more when it is all fully working.
>> >
>> >cheers,
>> >Alex
>> >
>> >On Tuesday 08 May 2012 09:37:47 David Wallom wrote:
>> >> Hi,
>> >>
>> >> Does anyone know of any work using the currently deployed SRM solutions
>> >>
>> >>on
>> >>
>> >> scalability both in terms of total volume stored in a single instance,
>> >> input bandwidth and I/o rates? Just thinking about possible solutions
>> >>
>> >>for
>> >>
>> >> SKA.
>> >>
>> >> Cheers
>> >>
>> >> David
>> >> --
>> >> ++++++++++++++++++++++++++++++++++++++++
>> >> Dr David Wallom
>> >> Associate Director Innovation, Oxford eResearch Centre
>> >> Technical Director, UK NGS
>> >> VP Communities, OGF
>> >>
>> >> Oxford eResearch Centre
>> >> 7 Keble Road
>> >> Oxford
>> >> OX1 3QG
>> >> UK
>> >>
>> >> Tel: +44 1865 610601
>> >> ++++++++++++++++++++++++++++++++++++++++
>
> --
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> | Dr. Alex Martin |
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> | Phone : +44-(0)20-7882-5033 Mile End Road, |
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