[Swift-devel] Re: [Dsl-seminar] REMINDER: discussion on dCache

[Ioan Raicu]

Hi,
Actually, I only heard of dCache when we used the Tier3 cluster for some 
of the Falkon experiments.  After reading up on dCache a bit, it seems 
like an interesting system, and hence decided to discuss it at the DSL 
Seminar. 

I do have some questions.  Does dCache run on dedicated machines 
(similar to the way GPFS does), or does every compute not runs the 
necessary dCache software to ensure that the compute node handles both 
the compute and storage needs?  I assume each node does both, but the 
next question is then how do applications do scheduling of application 
tasks on the compute/storage resources?  If done naively, lots of data 
will likely be moved from one node to another all the time... but if 
done right, and a cache-ware scheduler was in place, then application 
tasks could be scheduled on compute nodes that have the most data that 
is needed.  Do you know how this is handled in dCache?

Either way, I bet its pretty fast and scalable!  I am curious how much 
work there is left to invest in dCache to have a complete solution that 
is likely to be the most flexible and offer the best performance 
improvements given the particular hardware constraints that dCache is 
deployed on?

Thanks,
Ioan

Rob Gardner wrote:
> Mike,
>
> We have dcache deployed on our tier2 and tier3 centers here at UC -
>
> http://uct2-dc3.uchicago.edu:2288/
>
> but we've not yet done detailed scalability studies.  So far it has 
> met our needs but we've not yet hit it too hard.
>
> Rob
>
>
>
> On Apr 25, 2007, at 1:44 PM, Mike Wilde wrote:
>
>> I'm very interested in understanding dCache and its relationship to 
>> SRM and GridFTP better, as this is a critical topic for using OSG and 
>> running workflows there.  And for doing space management within 
>> workflows in general.
>>
>> Rob, Marco and Suchandra, all cc'ed here, might be able to point to 
>> the best docs.
>>
>> And there is a growing body of info on the OSG Storage Management 
>> wiki pages.
>>
>> It would be great for the Swift team to stay in the loop on this.
>>
>> - Mike
>>
>>
>> Ioan Raicu wrote, On 4/25/2007 1:36 PM:
>>> Hi everyone,
>>> We will have our weekly seminar tomorrow at 4:30PM in RI405.  
>>> Tomorrow's topic of discussion is dCache 
>>> (http://www.dcache.org/index.shtml).  I tried to find some detailed 
>>> papers on dCache's performance and scalability, but could not.
>>> I did find general and short papers about the architecture and 
>>> features of dCache:
>>>     * http://www.dcache.org/manuals/dcache-whitepaper-light.pdf
>>>     * http://www.dcache.org/manuals/dcache-dresden-sep-2006.pdf
>>>     * http://www.dcache.org/manuals/hepix-2006-paper.pdf
>>> We can discuss these, and if it seems interesting for our group, 
>>> keep looking for other more technical papers.  If anyone runs across 
>>> any technical papers on dCache and perhaps how it compares to GFarm 
>>> and GFS, please forward them on to the list. See you tomorrow,
>>> Ioan
>>
>> -- 
>> Mike Wilde
>> Computation Institute, University of Chicago
>> Math & Computer Science Division
>> Argonne National Laboratory
>> Argonne, IL   60439    USA
>> tel 630-252-7497 fax 630-252-1997
>

-- 
============================================
Ioan Raicu
Ph.D. Student
============================================
Distributed Systems Laboratory
Computer Science Department
University of Chicago
1100 E. 58th Street, Ryerson Hall
Chicago, IL 60637
============================================
Email: iraicu at cs.uchicago.edu
Web:   http://www.cs.uchicago.edu/~iraicu
       http://dsl.cs.uchicago.edu/
============================================
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