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CERN. What is CERN? Particle physics laboratory Europe old and new (plus collaborations with USA, Canada, Japan, India, Pakistan, Russia, China… ) Planning for ~5 PB per year, 2-5 GB/s in 2007: data storage problem!. Ski slopes. LHC ring. Geneva Airport. CERN: current tape situation.

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CERN

  • What is CERN? Particle physics laboratory
  • Europe old and new (plus collaborations with USA, Canada, Japan, India, Pakistan, Russia, China… )
  • Planning for ~5 PB per year, 2-5 GB/s in 2007: data storage problem!

Ski slopes..

LHC ring

Geneva Airport

cern current tape situation
CERN: current tape situation
  • Main drive: 9940B (50), already very busy
    • Peak test rate is ~ 1 GB/s
  • Secondary: 9840A (20), for ‘small’ files
    • Do we modernise to 9840C?
  • Main robotics: Powderhorn
  • Secondary: L700e (exotics, LTO1, SDLT..)
  • Efficiency is low, especially for read
  • Lots of drives needed now, so in 2007?
media
Media
  • Main media: 9940 200GC 13,600
  • Secondary: 9940 60GC 8,800
    • Being converted to 200GC, ~60% done
  • 9840 A
    • 2,100 user data (move to 200GC, reuse?)
    • 2,800 Legato data (legacy, reuse?)
    • 2,900 ADSM data (legacy, reuse?)
  • Oddities: SDLT, LTO, legacy 3590, DLT….
current plans
Current plans
  • Avoid purchase of 9840 or 9940 media
    • Re-use existing media as far as possible, OK in 2004, but 2005?
  • Consolidate backups, some aging out, but a lot of equipment! (virtualisation?)
    • 1 Timberwolf, 6 DLT700 for AFS
    • 2 Powderhorns, 14 IBM 3590E for ADSM
    • 2 Powderhorns, 6 STK 9840 for Legato
    • 1 Powderhorn, 4 STK 9940B for TSM
  • Decide on LHC system components in 2005
    • Call for Tender
      • Drive: STK, IBM 3592, LTO 2, other?
      • Library: STK Powderhorn/8500, IBM, ADIC Scalar 10000, other?
minimal drives for lhc
Minimal drives for LHC

Use at peak throughput assumed, realistically need 3 x this, > 3 x?

Powderhorns can cope re drive numbers (40/silo)…. But speed?

minimal drives
Minimal drives?
  • Write can be reasonably effective, often >50% of possible maximum
    • Many GB (10?) in one mount
    • Drive definitely streams
      • ~60s unit reserved/pick/load/position
      • 350s writing, say, for 9940B
      • ~60s rewind/unload/place
      • We write ANSI standard tape files, minimum 3s per file today…
  • Reading in CASTOR is poor, depends on files picked
    • 1 file, 1 GB, ~25% of possible maximum, depends heavily on robot speed
      • ~60s pick/load/position
      • 35s writing, say, for 9940B
      • ~60s rewind/unload/place
      • Some improvement in next CASTOR version… (marshalling requests)
  • But we READ more than we WRITE, except for data recording
minimal cartridge slots for lhc
Minimal cartridge slots for LHC

2010- 100K SAIT (or 78K 3592b?) is 18(14?) Powderhorns, so => new building?

2010- 100K SAIT is fine with 8500 in existing zones, but not supported

A ‘3592b’ does not exist today. SAIT exists, 500GB, ~30 MB/s..

costs for lhc 2010
Costs for LHC, 2010
  • Libraries: 20 8500 ~ 10 M $ (?) 33%
  • Media: 100K SAIT ~ 10 M $ (‘usually’ 100$/cart) 33%
  • Drives: ~300 SAIT ~ 10 M $ (‘usually’ 30 K$/drive) 33%
    • Why so many? Because read is poor at CERN but frequent..
  • However, drives/media in 8500 not a ‘monopoly’ problem
  • Today? Consider only major use, drives important…
  • Libraries: 6 Powderhorn ~ 1.5 M $ 28%
  • Media: 25 K 9940 ~ 2.5 M $ 28%
  • Drives: 50 9940B ~ 1.5 M $ 44%
major operational interests
Major operational interests
  • Benefits of 8500 very clear
    • 99.9% available machinery, easy upgrading…
    • Speed very helpful in disorganised reading, common at CERN
    • Drive/media mix very helpful (but might not be used..)
  • Benefits of SAIT-like capacity very clear
    • Higher capacity, no building needed
    • Data recording looks ‘easy’ at ~40 drives for 1 GByte/s
  • Linux driver from STK?
    • Hard to write your own and maintain it, hard to adapt to ‘new drive’ quickly
    • Might they eventually do this?
  • Better (WWW access)
    • Library/drive/media monitoring and logging features
    • Predictions of imminent failure, and timely requests for intervention
    • Access to MIR data for media monitoring, problem prediction, otherwise?
    • Customers ask for it, and it would save STK time, money…