User Board Input Tier Storage Review 21 November 2008 Glenn Patrick Rutherford Appleton Laboratory

2 UB: Castor Migration Path 21 December December CMS CSA06 worked and full production Castor service expected from Jan Plan to switch off dCache 30 June June June Original schedule unrealistic. Agreed that dCache would not be terminated until at least end 2007 and a minimum of 6 months notice to be given. 20 June June Separate ATLAS, CMS, LHCb & Gen Castor instances proposed. 24 June June Migration to be completed by end of November November Still on track...New building also looms. Castor Data

3 Name Server 2 stager DLF LSF stager DLF LSF 1 Diskserver Tape Server Oracle stager Oracle NS+ vmgr Name Server 1 +vmgr CMS Stager Instance Atlas Stager Instance LHCb Stager Instance Repack and Small User Stager Instance Diskservers Oracle DLF Oracle stager Oracle DLF Oracle stager Oracle DLF Oracle DLF Oracle repack Oracle stager Tape Server Tape Server Tape Server Tape Server Tape Server repack Shared Services UK Tier 1 – Castor2 Mass Storage UB Total = 2222TB

4 Background of Shrinking Capacity Terabyte(10 12 )/Tebibyte(2 40 ) amnesty. ~10% inflation for those experiments which applied. From 2007/Q4. Disk0Tape1 caches – overhead not included in (some experiment requests). Currently ATLAS TB, LHCb – 16.9TB, ALICE – 5.6TB (CMS – n/w buffers?). dCache & Castor Duplicate resources in dCache and Castor for experiment migration/testing/etc. From 2008/Q1 and before. 5% Castor storage inefficiency hit taken (plus capacity audit). Experiments get what their data requires! From 5 Nov and a background of Experiment Uncertainties

5... But Still Made it! No headroom! No reserve! LHC pledges ~met LHCb Start-up Allocations 2008/Q4

6 Who has what? ATLAS CMS LHCb Not much left over for other experiments! Reminder: For “Other”, GridPP3 proposal only had: T1 Disk 2008 = 18TB T1 Disk 2009 = 31TB T1 Tape 2008 = 180TB T1 Tape 2009 = 310TB T1 CPU = 0 CASTOR ONLY

7 Required xrootd (not been highest Castor priority). Finally, in ALICE production Oct Low on manpower. Suffer from no RAL involvement. Getting back on track for 2009 (5.6TB disk0 to go to ~90TB). Communications improved (e.g. Cristina). “Other” Experiments 1 ALICE: ALICE: No storage resources deployed in Castor for most of 2008 (requirements revised downwards, deprecated due to h/w delays and ATLAS/CMS/LHCb given priority for CCRC08). MINOS MINOS: Still migrating dCache/NFS data. Also, MC system draws down several hundred flux files from Castor at start of each job – Castor seems to manage load even from multiple jobs (except for some benign errors). Double disk allowance for migration – last overdraft left? Limited manpower. Batch jobs submitted to UK Tier 1

8 “Other” Experiments 2 Silicon Detector Design Study: Silicon Detector Design Study: Urgent simulation required for physics benchmarks in Letter of Intent (due April 2009). Enhanced CPU allocation (268KSI2K) in absence of LHC work. 4M events reconstructed out of simulated 8M. Castor server deployed+SRM for staging to SLAC, but took time to deploy (PPD Tier2 helped out in meantime). Need to be able to be flexible for this sort of sudden activity... MICE: MICE: Currently setting up. RAL is “Tier 0” for experiment – pseudo real-time beam tuning, data distribution, etc. Castor server deployed and MICE currently setting up. BaBar: BaBar: The end approaches … long story since ~Sept. 2006! 49.6TB in NFS disk + ADS tape (35TB alloc). UKQCD: UKQCD: Plan to access Tier 1 via SRM. Large bid for Tier 1 tape submitted to HPC call. Need to engage on technical deployment (require 30TB disk, 1.8TB NFS so far). VO enabled, memory requirements?

9 Farewell (sort of)... For lingering legacy experiments still in dCache, “others” and new small VOs, probably give some minimal deployment in Castor…. shared disk pool. Others!

10 On the Horizon... T2K: On the horizon for Some disk already pre-allocated. 16TB out of 20TB. NA48/3: On the horizon for Some disk pre-allocated. 25TB out of 50TB. SUPER-B?: Depends on UK proposals. No allocation yet. ~5 TB disk1tape1 growing from mid SUPERNEMO: Mainly Tier 2 so far. Yet to feature at Tier1 (except perhaps under “other”). No storage allocation.

11 Apr 2007 Oct 2008 Apr - Sep 2007 Castor Experiment Planning Once allocations and overall strategy are agreed in UB, it is up to experiments to engage with T1 team over storage classes, space tokens, SRM end-points, etc. Series of weekly meetings evolved to deal with Castor technical issues. Monthly meetings for (mainly) other Tier 1 issues. Success of experiments correlated with how well they engage at these. Castor Bumpy Ride

12 Looking Forward Cant keep everybody happy all of the time. PPRP numbers are assumed for LHC experiments and smaller experiments only get the scraps that are left over. What will real LHC data look like? Background, increased event sizes, trigger rates, etc. can swallow up resources for the smaller experiments. What are the error bars? Won’t know until later in 2009… Smaller experiments (including ALICE) limited by manpower. Good communications + technical help (e.g. Janusz, Shaun, Matt, Catalin, Derek…) and documentation (Stephen) vital. Evolution of regular (weekly/monthly) storage/T1 meetings very successful and efficient. Need to be more pro-active here (make it part of process and condition of deploying allocations). Improve disk deployment and make more flexible (server quantisation). Easy for me to say of course. Need to be realistic about effort all this takes (T1+expts)!