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Aleph computing after 2000

Aleph computing after 2000

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Aleph computing after 2000

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  1. Aleph computing after 2000 • Falcon • Linux • shift50 • Access to data Marco Cattaneo, Aleph plenary in Siena, 1st October 1999

  2. Plans for Falcon (and ALWS) • Data-taking ends 9/2000 • Reprocessing of 2000 data possible well before Xmas • Complete reprocessing of LEP II data? • Falcon will be kept in Echenevex until 12/2001 • From 2002, keep in building 2: • at least one machine running VMS • ALNEWS - unless we find and alternative • connected to at least one DLT drive • Access to (small quantities of) raw data • How long do we want (VMS) access to raw data? • Do we archive it? How (copy to different format)? Where?

  3. LEP II reprocessing • Falcon at full speed: 10pb-1 per day • Integrated luminosities 1996 1997 1998 1999 2000 Total21.5 68.2 182.7 192+50? 200? ~700 pb-1(on 27/9) • Will take ~3 months for the data • Assumes all calibrations / alignment ready on time • Assumes no mistakes • Neither was true for LEP I reprocessing.... • MonteCarlo took much longer.... • I think we cannot start any later than spring 2001 • Decision by September 2000 • Test with 2000 end of year reprocessing? • Then work backwards through the years

  4. An aside: • In 1999 we will have collected ~240pb-1 • Run ends 7th November • Xmas shutdown from 18th December • 24 days needed to reprocess • Latest possible start is 24th November • Aim for: • Reprocessing of Z0’s on weekend of 13th November • 5 days of checks, then: • Start reprocessing of high energy on weekend of 20th November • This is very tight! • Must start now to assemble the pieces....

  5. Linux support • Many labs have (or plan) large Linux facilities • e.g. IN2P3, RAL, Pisa, Glasgow, Lancaster, NBI, ... • e.g. CERN: • LXPLUS (interactive) service since June, 3*shift50 by November • LXBATCH 4*shift50 from November • PCSF (currently WNT, largely Linux in 2000) up to 5*(HP)CSF • Aleph will have in 2000: • roughly equal quotas on CSF and “Linux PCSF” (insufficient capacity on CSF to satisfy requests of the 4 LEP experiments) • “sizeable” quota on LXBATCH • Aleph software already runs on Linux • Thanks to Anders Waananen and the NBI team • Extensive checks by David Smith and Stephane Jezequel • some minor precision-related differences • KINGAL is missing

  6. Linux support proposal • Clearly we must support Linux officially in Aleph • Before end of year for everything already ported • For most used generators • Other generators on request • Can Aleph support 4 Operating Systems at CERN? • Everything is possible, but: • HP OS frozen at HPUX10 • No new HP investment at CERN, future of CSF unclear • DROP official HPUX support at end 2000 • One year overlap with Linux support • Interested institute(s) could take over support • c.f. NBI for Linux

  7. What about Digital Unix? • SHIFT50: • Support and maintenance is currently approved until end 2002 • ALEPH will request to extend this to end 2003 if we reprocess • Aloha (and the homelabs) • Huge investment, and huge capacity on aloha • However: • CERN/IT proposal to “minimise RISC” by end 2001 • Freeze OS support to DUX 4.0F (probably obsolete end 2001) • What about Aleph analysis after 2002/2003? • So: • We MUST support DUX until end of major analyses • We SHOULD discourage further investment in DUX hardware • 2002/2003 could be tough (in particular for shift50)

  8. Shift50, the final act • It COULD be that, earlier than 2003: • SHIFT50 will be small fraction of CPU used by Aleph • The majority of analyses will have shifted to Linux • The maintenance of SHIFT50 has become problematic • If all of the above, we could imagine switching off shift50 BEFORE end of 2002 • Of course, disks would be mounted elsewhere • This is decoupled from any decision for aloha and DUX support

  9. And after 2002/2003? • Encourage migration away from DUX A.S.A.P. • Make Aleph environment “independent” of shift50 • Move scratch areas, EDIRs and user workspace to AFS • Continue to access ntuples via RFIO from shift50 /wg disks (more efficient than AFS) • Stage pool is already accessible from any authorised CERN client • Take advantage of huge public Linux capacity coming online • Make available Aleph Linux customisation for desktop PCs • With a little gentle pushing, physics analysis will follow CPU... • Transparent continuation of analyses after 2003 • Can continue on CERN public batch (hopefully Linux....) • Can switch off SHIFT50 without side-effects • Can drop support for DUX without side-effects

  10. But what about the data? • EPIO/BOS not supported outside Aleph • Tape media become rapidly obsolete: • 1995: move from 3480 to DLT 2000 • 1998: move from DLT 2000 to STK Redwood • 3480 no longer available at CERN • 2000: STK Redwood discouraged, use STK 9840 • No DLT 2000 robot, rare manual mounts possible • 2003: ? • Do we want to archive our data? • What (MINI/DST/POT, which MC) • How? (Copy to next generation tape? OO database?) • What about analysis tools?

  11. Data Analysis tools • ALPHA++ • A first version for doing “real” user analysis is available for tests! • M.Hörndl (summer student) has shown that it is possible to perform a QCD analysis • (however, for the moment only small statistics) • Everybody interested should • Look at the Web page • http://alephwww.cern.ch/~disserto/objty/Welcome.html • ( Aleph home page -> Offline system -> ALPHA++ ) • Contact G.Dissertori • New SCANBOOK implementation (A.Bonissent, F.Loverre, J.Boucrot) • JAVA client accessing ORACLE database at CERN • Light client, single database copy, easier maintenance, better performance over network • Available for testing now.

  12. DISCUSSION • Last reasonable date for LEPII reprocessing? • How long do we need/want access to raw data? • And ALNEWS? • Support Linux now? Drop HP support end 2000? • Are long term plans for DUX/shift50 reasonable? • Should we worry about archiving the data?