Analysis Operations Experience

1. Analysis Operations Experience 2010 highlights 2011 work list Analysis Operation report at CMS week

2. Analysis Metrics • Overall status tracked weekly with summary mails sent to AnalysisOperations forum and with series of graphs • https://hypernews.cern.ch/HyperNews/CMS/get/analysisoperations/189.html • https://hypernews.cern.ch/HyperNews/CMS/get/analysisoperations/192.html • https://twiki.cern.ch/twiki/bin/view/CMS/AnalysisOpsMetricsPlots • Allows us to see the forest while watching daily the trees Analysis Operation report at CMS week

3. Lot’s of analsys jobs Job wrapper time (avg.last week) Production: 5h Analysis: 2h JobRobot: 20min • More analysis then production jobs, but shorter (not much) • Load on infrastructure scales with #jobs • Until Crab3 (at least) could only improve job duration via user education • Education campaigns need tools and effort • Not much room left for more jobs • #jobs running at same time (i.e. used slots) is showing saturation Analysis Operation report at CMS week

4. Too many jobs ? • It is a success of CMS that so many users manage to run so much data processing • But expect more frustration as waiting time grows • May also expose to new failure modes (like any new regime, so far) Analysis Operation report at CMS week

5. Too much data ? Dec. 5th, 2010, 19:45 o‘clockDuring Deletion Campaign • Space centrally managed by Analysis Operations (2.7 PB) is ~full 2029 TB used by AnOps 1.5 of 3.75 PB free at official group sites • AnOps just cleaned up in preparation for 39 based reprocessing • AnOps can no longer host all commonly used versions of MC and data • MC for two energies (7TeV and 8TeV(?)), with and w/o pile-up, two releases • data for two releases • Unlikely that all of this will fit into central space unless we switch to AOD distribution only • Expect physics group to use more of their space in 2011 Analysis Operation report at CMS week

6. Caring for user’s data: placement To T2s From T2s • in 2010 • 17 PB transferred to T2s • 4.5 PB transferred from T2s • Central space completely refreshed about every3 months • Data distribution works quite well Analysis Operation report at CMS week

7. Elevates datasets from local to global DBS and PhEDEx Two instances deployed: RWTH Aachen, Imperial College London Three part time operators, Th. Kress, M. Giffels and M. Cutajar StoreResults monitoring developed in 2010 Access restricted to group representatives for performance reasons Allows physics groups to monitor their requests in real time Very useful for the operators, too. For example StdOut and StdErr of retrieved jobs are directly available Caring for user’s data: StoreResults Service • average 1-2 requests per day usually in bunches of 2-10 • 340 requests in 2010, ~98% elevated successfully • average time for the elevation 46 hours, however 3000 job requests from SUSY take its time Analysis Operation report at CMS week

8. StoreResults Future Development • re-implement StoreResults in WMAgent • support growing datasets natively • RequestManager will be used for data processing requests • Combines the possibility of making request, approvals by authorized people as well as tracking of the request in a single place, replace current Savannah interface • Development schedule and support will be discussed with Computing/Offline Management this week Analysis Operation report at CMS week

9. Caring for user’s data: transfer • Users need to move data from one T2 to another T2 • To offer more routes/bandwidth to data replication • To replicate data elevated via StoreResult • To collect CRAB outputs staged out at job execution • Requires • Staging area /store/temp/user at each site • Transfer link amon all T2’s (full mesh) • Consistent deployment on large distributed system • Simple, well defined goal • Persistent, patient month-long effort Analysis Operation report at CMS week

10. Commissioning data transfer infrastructure • Local CRAB stage out validated at 41/48 sites • 3 of the missing 7 fails due to known Crab shortcoming Analysis Operation report at CMS week

11. Caring for user’s jobs: crab feedback Mail volume (#messages) handled by Analysis Operations on the CrabFeedback forum in 2010 • Support more then 400 different users every week • Cater from data lookup to grid and site problems • Draw a line at “cmsRun” (could be easier with better reporting, often users do not know how to read cmsRun exit codes) • Not possible to help w/o extensive experience and knowledge of the crab, grid, facilities internals, several attempts at bringin in new personnel,failed with “I have no idea how to help here” Analysis Operation report at CMS week

12. Caring for user’s jobs: Crab Server • Running 6 now: 2 at CERN, 2 at UCSD, 1 each at Bari and DESY • By operational choice one in drain at any time to allow DB reset • Other issues continously pop-up (from hw to sw) and usually have 4 or less • Good side • Installed, operated and by large debugged by non-developers • Much improved after last summer developers effort • More then 50% of the analysis jobs run through Crab Servers • Most of the time: simply work • Bad side • Operationally heavy • jobs/task tracking can fail and users need to resubmit • Resubmission ackward at times • Status reporting obscure at times, leads to unnecessary help requests Analysis Operation report at CMS week

13. Give us a hand ! How to be a good user • Read and use documentation • Give all information in the first message, before we need to ask • crab.cfg, crab.log, relevant stdout/err, dashboard URL .. • Do not use blindly config. files you do not understand • Make some effort to figure out the problem yourself (in the end it will save you time) • Do not expect solution in “minutes”, be prepared for “tomorrow” • Get trained before you need to do something in a rush, ramp up in steps: 1 job, 10 jobs, 100 jobs, … • If you see time-critical CRAB work ahead :  Get hands on experience now Analysis Operation report at CMS week

14. The good (2010 highlights) • Users do a lot of analysis work • We believe we know what’s going on • Grid works • At least as well as our tools • We never have something as easy and simple as “service X at site Y is broken since a day and nobody noticed” • We have replaced developers in crab server daily ops and crab feedback daily support • No service deterioration for user’s community • We care successfully for large amount of data Analysis Operation report at CMS week

15. The bad (current concerns) • We are reaching the point of being resource constrained • Many decisions were made easy by abundance • do no debug: resubmit • do not fix site: replicate data • Doing better requires thinking, planning, following up daily and better tools  i.e. human time • Crab2 is in maintenance mode, while still operationally heavy • Working in firefighting / complain-driven mode much more then desired (and expected) • As feared transient random problems in the infrastructure are main effort drain • More and more difficult to find manpower willing to work here • Maybe collaboration was expecting effort here to be ramping down by now ? Analysis Operation report at CMS week

16. The ugly (more work in 2011) • Major technology transistion looming ahead (Crab3) • Can we spare operation resources for the transition ? • More new things coming down the pipeline • DBS3 • Something new in monitoring • Multicore processing • New data access methods/patterns • Distributed system stays distributed but dependencies among sites grow as WAN boundary gets fainter • Very fast and very performat connection does not take away having to deal with two different systems • Nothing as easy and basic as copying one file from here to there, yet figuring out why data does not move in PhEDEx is still something only a handful of people can do Analysis Operation report at CMS week

17. The year that comes • Things we need to do in 2011 (and following) for a brighter future • Besides all we already do and need to keep doing • Work on job monitoring and error reporting • Not good enough yet to tell where exactly resources are wasted and how to fix • Work on crab servers monitoring, current one not good enough to • avoid complain-driven mode • spot systemic problems in server or middleware • Work on user problem reporting • Reduce number of mail iterations • Learn how to use sites of very different size and reliability • Since we may need all of them • Work on better alignement of FacOps site testing with AnOps reality (continous effort) Analysis Operation report at CMS week

18. Summary • Analysis metrics • High level overview: under control • Error/efficiency reporting: work to do • Data placement and transfer for physics users • Centrally managed storage area: OK but filling up • T2-T2 transfer links: success story • Group data distribution: OK but need to transition to new tool • CRAB operations • Crab feedback: unsubstainable since 1 year, but coping • Crab server: works, but too much operationally heavy • Local stageout: storage commissioned, need to validate tool • Concerns • End of abundant resources era: more work needed • New tools coming: more work needed • Things to work on in 2011: pretty long list given we should be in steady operations Analysis Operation report at CMS week