1. R. Graciani for LHCb Mumbay, Feb 2006
LHCb Plans for SC4
R. Graciani for LHCb
Mumbay, Feb 2006

2. LHCb Plans for SC4 (Mumbay, Feb 2006)
Overview
The LHCb Computing Model
Storage Classes
LHCb DC06
LHCb SC4
Aim
Preparation
SC4
Outlook
LHCb Plans for SC4 (Mumbay, Feb 2006)

3. LHCb Plans for SC4 (Mumbay, Feb 2006)
LHCb Computing Model
LHCb Plans for SC4 (Mumbay, Feb 2006)

4. LHCb Computing Model (I)
RAW data distribution:
Tier-0 -> Tier-1’s
Stored on MSS for resilience
Data Tier-1’s + Tier-0
First pass: RAW still on MSS disk cache
Second pass: RAW retrieved from MSS
Note 50% of re-processing at Online Farm.
Produce rDST, stored on MSS
LHCb Plans for SC4 (Mumbay, Feb 2006)

5. LHCb Computing Model (II)
Stripping (filtering, streaming, skimming…)
First pass: rDST and RAW still on MSS cache
Later pass: rDST and RAW from MSS
Produces DST for analysis:
distributed to ALL Tier-1’s+CAF+few large Tier-2
MSS at producer site
Disk replicas at ALL Sites
Analysis of DST:
DST from disk
Produces User data (N-tuples, ETC, mini-DST…)
LHCb Plans for SC4 (Mumbay, Feb 2006)

6. LHCb Computing Model (III)
Simulation
temporary storage at Tier-2 (“volatile” disk)
rDST transferred to associated Tier-1 (including CERN)
from then on, similar to real data
Tier-1’s
DST distributed to CAF + 1 additional Tier-1
MSS + disk
Available on disk
Other activities: alignment, calibration, detector studies,…
LHCb Plans for SC4 (Mumbay, Feb 2006)

7. Data|Storage Classes (I)
Single|Double copy, MSS, + disk cache
RAW (Tier-1 + Tier-0), rDST (at Tier-1 production site)
Production access for reprocessing
Multiple copies, permanently on disk
DST (CAF+Tier-1s+few large Tier-2s)
More than one version of all DSTs (at least 2 latest)
Efficient access needed from WNs (IO bound analysis)
LHCb Plans for SC4 (Mumbay, Feb 2006)

8. Data|Storage Classes (II)
Single copy user files, on disk, reliability needed
mini-DSTs, Ntuples (AOD)…
created outside control from the VO-manager
possibly small files (down to 10’s of MBytes)
needs high reliability or MSS backup
permanently available on disk (quota!)
Ancillary files
DIRAC sandboxes (disk-only)
Production logfiles (disk-only): web access required
LHCb Plans for SC4 (Mumbay, Feb 2006)

9. LHCb DC06 “Test of LHCb Computing Model using LCG Production Services”
Distribution of RAW data
Reconstruction + Stripping
DST redistribution
User Analysis
MC Production
Use of Condition DB (Alignment + Calibration)
LHCb Plans for SC4 (Mumbay, Feb 2006)

10. LHCb Plans for SC4 (Mumbay, Feb 2006)
SC4 Aim for LHCb
Test Data Processing part of CM
Use 200 M MC RAW events:
Distribute
Reconstruct
Stripped and Re-distribute
Simultaneous activities:
MC production
User Analysis
LHCb Plans for SC4 (Mumbay, Feb 2006)

11. LHCb Plans for SC4 (Mumbay, Feb 2006)
Preparation for SC4
Event generation, detector simulation & digitization
100M B-physics + 100M min bias events:
3.7 MSI2k · month required (~2-3 months)
125 TB on MSS at Tier-0 (keep MC True)
Timing:
Start productions mid March,
Full capacity end March
LHCb Plans for SC4 (Mumbay, Feb 2006)

12. LHCb Plans for SC4 (Mumbay, Feb 2006)
LHCb SC4 (I)
Timing:
Start June
Duration 2 months
Distribution of RAW data
Tier0 MSS SRM  Tier1’s MSS SRM
2 TB/day out of CERN
125 TB on Tier1’s
LHCb Plans for SC4 (Mumbay, Feb 2006)

13. LHCb Plans for SC4 (Mumbay, Feb 2006)
LHCb SC4 (II)
Reconstruction/stripping
270 kSi2k · month
60 TB on Tier1’s (full DST)
1k Job/day (following the data)
Jobs duration 2 hour
90 % Jobs (Rec): Input 3.6 GB Output 2 GB
10% Jobs (Strip): Input 20 GB Output 0.5 GB
DST Distribution
2.2 TB on Disk / Tier1 + CAF (selected DST+RAW)
LHCb Plans for SC4 (Mumbay, Feb 2006)

14. LHCb Plans for SC4 (Mumbay, Feb 2006)
DIRAC Tools & LCG
DIRAC Transfer Tier-0 + Tier-1’s
FTS + SRM
DIRAC Production Tools
Production Manager console
Transformation Agents
DIRAC WMS
LFC + RB + CE
Applications:
GFAL: Posix I/O via LFN
LHCb Plans for SC4 (Mumbay, Feb 2006)

15. LHCb Plans for SC4 (Mumbay, Feb 2006)
To be Tested after SC4
Data Management:
SRM v2
gridFTP 2
FPS
Workload Management:
gLite RB ?
gLite CE ?
VOMS
Integration with MW
Applications
Xrootd
LHCb Plans for SC4 (Mumbay, Feb 2006)

16. LHCb Plans for SC4 (Mumbay, Feb 2006)
Outlook
DC06:
Data processing test (SC4)
MC Production
User Analysis
Check of LHCb Computing Model
LCG Production Services not in place
LHCb Plans for SC4 (Mumbay, Feb 2006)