LHCb Quarterly Report

October 2008

PhC 2

Core Software (Gaudi)

m Stable version was ready for 2008 data takingo Gaudi based on latest LCG 55ao Applications ready for using survey geometry,

conditionsDBP Still difficulties in commissioning CondDB access at

Tier1sm Plans for the shutdown

o Use opportunity for “cleaning” part of the framework

P Unifying some interfaces, remove obsolete parts…o New ROOT schema evolution

P Under investigation (POOL)o Support file-related records

P Needed for file summary records (luminosity, statistics for skimming etc…)

o More on interactivity (GaudiPython)o Merger with ATLAS on “configurables”

P Python-based configuration of applicationso Some improvements for Online usageo Studies on multi-core support (parallel file

processing)P In collaboration with LCG-AA / PH-SFT

LHCb QR, October 2008

PhC 3

LHCb recent activities

m Commissioning of DIRAC3o Fully reengineered systemo Main features:

P Single framework for services, clients and agentsP Fully integrated Workload and Data Management

SystemsP Supports production and user analysis activities

d Allow to apply VO policy: priorities, quotas…P Uses pilot jobs as DIRAC2

d Ready for using generic pilot jobs (not switched on yet)d Full scale test with generic pilots will take place in the

coming weeksP New bookkeeping system (also integrated)

m Production activitieso Complete simulation and stripping of MC data (so-

called DC06 as was launched in 2006)o CCRC-like activity at low rate (10%)o Start 2008 simulation

P Mainly for alignment and calibration studiesP Wait for first data for tuning generators and detector

responseLHCb QR, October 2008

PhC 4

Recent issues encountered

m Storageo Instability of SEs, in particular dCache

P Very good response from sites and dCache developersP Permanent struggle due to various causes:

d Software issues (addressed with sites and developers)d Sub-optimal hardware configuration at some Tier1’sd Unavailability of files: are in the namespace at site but

cannot be accessed or even get a tURL Damaged tapes, unavailable servers…

o Transfers are OK (low throughput needed: 70 MB/s)m Workload Management

o Three severe issues with WMSP Mixing up credentials of jobs submitted by the same

user with different rolesP Limitation in proxy handling (too few delegations

allowed) preventing some users to run jobs (e.g. from French CA)

P Misbehavior of WMS after some idle time: cannot find suitable sites even for a job without requirements!

m Issues with local shared software repository at sites

o Stability and access rights (being addressed)LHCb QR, October 2008

PhC 5

Outlook for DIRAC

m DIRAC3 will be fully ready for first datao Analysis will have fully migratedo End of September: no dependency any longer on

SRM v1 (legacy files)m Still to come:

o Glexec on worker nodesP Will allow to exploit the full power of DIRAC

d Allows late binding of jobs, VO policy etc…P Running analysis jobs with higher priority without site

interventionP DIRAC3 model was certified long ago by the GDB working

groupP Waiting for middleware to be ready (SCAS service)

o Commissioning of the alignment and calibration loopP Setting up an LHCb-CAF (Calibration and Alignment

Facility)d Requirements are rather modest (“simple” detector)d Start with 2 8-core machines, 200 GB of disk

P Full commissioning of Conditions Database update and streaming

d Currently very few commits to CondDBLHCb QR, October 2008

PhC 6

LHCb delayed startup

m Not clear whether this is a longer or advanced shutdown…

m LHCb can’t make much use of cosmics…o Vertical detectors

m More simulation will be needed for replacing 2008 data in commissioning

o Alignment and calibrationo Full chain (including HLT)

m Calibration and Alignment (CAF)o Survey of Calibration done on the Online monitoring

farmo Low rate (~5 Hz) calibration stream to Tier0

P Reconstructed promptly (smallish files on D1 storage)o Calibration loop triggered by this monitoring

P Stop automatic reconstructionP Run calibration and alignment

d At CERN (CAF): dedicated queues set up (currently 20 slots)P Validation of calibration

d At CERN (Tier0) using the calibration streamLHCb QR, October 2008

PhC 7

Full Dress Rehearsal

m Complete commissioning of:o HLT (for early and further data)

P Algorithms, memory leaks…o Event streaming and real data online monitoring

P Started with first beams but…o Automatic transfers and reconstruction (à la CCRC)o Calibration loop

m Preparatory phase:o Large samples (as available, events can be reused)

of minimum bias eventso Online injection software (mimicking Front-End

electronics)m Time scale:

o Ready in Januaryo Actual date depends on maintenance (cooling) at the

pitP February of March for the testP Typically running every other week, interleaved with pit

commissioning activitiesLHCb QR, October 2008

PhC 8

Resources

m No plan to change the resource needs after the LHC incident

o 2008 data was small anyhow, no influence on the future

o Give priority to required activitieso Low pace generic activity

P “Keep the machine warn”…P Verify all Grid services (storage, transfers, WMS…)P Scrap not needed data

m Reassessing the needs at CERN in particularo First data and hot checks better done at CERN

P Already 25% of analysis anticipated in TDRo Better understanding of

P Calibration needs (monitoring and validation)P Needs for analysisP Include software testing and validation activities (non

negligible)m Need to have better control on user activities

o How to avoid a single user to exhaust VO’s share?LHCb QR, October 2008