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Using the Grid- a users perspective Ivan Hollins University of Birmingham.

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Presentation on theme: "Using the Grid- a users perspective Ivan Hollins University of Birmingham."— Presentation transcript:

1 Using the Grid- a users perspective Ivan Hollins University of Birmingham

2 What I have been doing… Using the Light Grid Submission Framework https://uimon.cern.ch/twiki/bin/view/Atlas/LJSFGettingStarted Doing Full Simulation with atlas software only Have run ~400k Full Sim events equating to ~ 32K jobs on the Grid, from July to date. Warning Am very much a novice user Experiences are heavily dependant on the Ljsf, which sitting on top of the grid tools may be as much responsible for some of my experiences

3 Summary of Nice things… Good documentation REALY helps to understand the tools Hello world example very nice Once language mastered operations seem fairly intuitive Ranking and Interactive features v nice (although sometimes felt a little in the dark as which was the most appropriate way to Rank sites) Ganglia tool RAL has nice, also Gstat er%2fcsflnx353.rl.ac.uk&m=%5Bnone%5D&r=day&s=descendinghttp://ganglia.gridpp.rl.ac.uk/specials/pbs.php?h=OpenPBS%20serv er%2fcsflnx353.rl.ac.uk&m=%5Bnone%5D&r=day&s=descending

4 Summary of Not so Nice things… Getting Started Getting all my certificates and registering seemed complicated / unclear. Would be useful to have an idiots guide, step by step. Also unclear which VO I should join (atlas has different options) Running Sites that advertise software versions that arent installed properly. –Could there be a monitoring tool to periodically test the sites to weed these out? Some jobs just Hang! – absolutely no idea why. Would be nice to be able to see how much cpu jobs are using then could tell easily which have hung. Resource Brokers – can be a bit temperamental. Had to keep changing these, not obvious at first how to do this. Can the RBs be hidden? Registering files to the Grid – overall works well with a couple of exceptions. –You seem to be able to overwrite a catalogue entry with a new file, however the storage element doesnt allow files to be rewritten. End result Cat ID != File ID –Can also register a non-existent file! Not sure if this is a Grid or Ljsf thing… Storage Elements –Not immediately obvious where to store data, what were the choices etc –CASTOR – obviously not directly a Grid problem, but has been a big source of pain. Once a file goes onto tape since the retrieval time long, your job times out and ends.


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