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A UK Computing Facility

A UK Computing Facility. John Gordon RAL. Data Size. Event Rate 10 9 events/year Storage Requirements (real & simulated data) ~300TByte/year UK Physicists want access to data for analysis 2TB in 1999, 4TB/year 2000 on data and simulation. Why don’t UK Physicists use SLAC?.

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A UK Computing Facility

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  1. A UK Computing Facility John Gordon RAL

  2. Data Size • Event Rate 109 events/year • Storage Requirements (real & simulated data) ~300TByte/year • UK Physicists want access to data for analysis • 2TB in 1999, 4TB/year 2000 on data and simulation HEPiX Fall ‘99

  3. Why don’t UK Physicists use SLAC? ….and SLAC is already heavily used. HEPiX Fall ‘99

  4. Existing UK Facilities • Shared facilities in UK are HP, Intel/Linux and Intel/NT. • BaBar mainly use Suns • Historically, UK lacking in Suns in HEP departments • BaBar have Sun E3500, 4 cpus, 2GB of memory at RAL - Bought for program development • Several hundred GB of disk • Plus a few desktop machines in universities HEPiX Fall ‘99

  5. BaBar bid for more • BaBar went to a UK Government research fund and bid for $1.8M for UK BaBar facilities • They were awarded ~$1.2M at the start of this year for: • A central server at RAL with several TB which will receive data from SLAC. • Server and disk in 10 UK universities • Co-operating databases across the UK • One extra staff member to achieve this HEPiX Fall ‘99

  6. E4500 server - • 6x400MHz cpus, 4GB memory • 5TB of formatted disk in 27 A1000 RAID arrays • 6 UWSCSI busses • DLT7000 stacker • 7 fast ethernet adaptors • E450, 3x400MHzcpus, 2GB • 5x A1000, = 1TB E250, 2 x400MHz cpus, 1GB, 3xA1000 = 0.5TB Actual Equipment • Sun vs Compaq • Sun won. • RAL • 5 Universities (Bristol, Edinburgh,Imperial, Liverpool, Manchester) with 4 Universities (Birmingham, Brunel, QMW, RHBNC) with HEPiX Fall ‘99

  7. Setup at RAL (early experience) • Equipment delivered and installed • Filesystems limited to 1TB • used 4xA1000 => 720GB striped(?) • 5.5 Million events brought from SLAC • E3500 acts as a front-end, E4500 holds data, both runs batch jobs • E4500 also AMS server to other systems. • LSF cluster on 2 Suns. • Who else is running large data on Suns? HEPiX Fall ‘99

  8. OOSS • Andy Hanushevsky visited in September and installed his OOFS and OOSS • This provides a layer which interfaces Objectivity to the Atlas Datastore (cf HPSS at SLAC) • All the disk space runs under the control of OOS which acts as a cache manager • Current level of Objectivity/AMS doesn’t allow OOS to retrieve data transparently from the robot but data can be easily brought on-line by prestaging HEPiX Fall ‘99

  9. Network Plans • A single server in a university on fast ethernet can suck data from RAL at rates which will be unpopular with other sharing the institutes connections to the WAN. • Pilot to establish tunnels over JANET using spare ATM capacity HEPiX Fall ‘99

  10. 2MB 2MB Manchester SuperJanet IC RAL HEPiX Fall ‘99

  11. Purpose of Trial • Since bandwidth will be small the trial will not necessarily give better throughput • Establish whether end-to-end connection over PVCs works • Establish whether the different management domains can reach a common, working solution • Check that the routing works • Should be simple to increase bandwidth later HEPiX Fall ‘99

  12. Original Data Model • Data to RAL by tape • Model I - all TAG data at other sites; pull detailed data from RAL • Model II - frequently-accessed events stored in full at other sites; replication from RAL • Investigate methods of copying, updating, replicating databases over WAN HEPiX Fall ‘99

  13. New Data Model(?) • BaBar currently has performance limitations • Working on non-Objectivity solution NOTMA • DST using ROOT i/o • 10**9 events = 280GB • Likely that universities will want all events locally • Detailed events stored at RAL in Objectivity HEPiX Fall ‘99

  14. Conclusion • RAL moving in opposite direction from HEPCCC proposal - more flavours of unix on new hardware platform. BaBar will be using Linux soon for simulation though • A bigger scale of disk data handling for one experiment. • Data synchronisation over WAN • (SLAC-RAL-UK Universities) HEPiX Fall ‘99

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