Stefano Belforte Analysis Operation report at CMS week

Dec 7, 2010 1

Analysis Operations Experience

2010 highlights2011 work list

Dec 7, 2010Analysis Operation report at CMS week

2Stefano Belforte

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

Dec 7, 2010Analysis Operation report at CMS week

3Stefano Belforte

Lot’s of analsys jobs

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

Job wrapper time (avg.last week)

Analysis: 2h

Production: 5h

JobRobot: 20min

Dec 7, 2010Analysis Operation report at CMS week

4Stefano Belforte

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)

Dec 7, 2010Analysis Operation report at CMS week

5Stefano Belforte

Too much data ?

Space centrally managed by Analysis Operations (2.7 PB) is ~full

Dec. 5th, 2010, 19:45 o‘clockDuring Deletion Campaign

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

2029 TB usedby AnOps

1.5 of 3.75 PB free at official group sites

Dec 7, 2010Analysis Operation report at CMS week

6Stefano Belforte

Caring for user’s data: placement

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

To T2s

From T2s

Dec 7, 2010Analysis Operation report at CMS week

7Stefano Belforte

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

Dec 7, 2010Analysis Operation report at CMS week

8Stefano Belforte

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

Dec 7, 2010Analysis Operation report at CMS week

9Stefano Belforte

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

Dec 7, 2010Analysis Operation report at CMS week

10Stefano Belforte

Commissioning data transfer infrastructure

Local CRAB stage out validated at 41/48 sites

3 of the missing 7 fails due to known Crab shortcoming

Dec 7, 2010Analysis Operation report at CMS week

11Stefano Belforte

Caring for user’s jobs: crab feedback

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”

Mail volume (#messages) handled by Analysis Operations on the CrabFeedback forum in 2010

Dec 7, 2010Analysis Operation report at CMS week

12Stefano Belforte

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

Dec 7, 2010Analysis Operation report at CMS week

13Stefano Belforte

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

Dec 7, 2010Analysis Operation report at CMS week

14Stefano Belforte

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

Dec 7, 2010Analysis Operation report at CMS week

15Stefano Belforte

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 ?

Dec 7, 2010Analysis Operation report at CMS week

16Stefano Belforte

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

Dec 7, 2010Analysis Operation report at CMS week

17Stefano Belforte

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)

Dec 7, 2010Analysis Operation report at CMS week

18Stefano Belforte

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