• 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!

LHC ring

Geneva Airport

Ski slopes..

CERN

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?

Current usage: ~150 Mbytes/s

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

• 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?

Estimations for LHC

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0.5

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2006 2008 2010

GB/s

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Petabyte

Minimal drives for LHC

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20

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9940B

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20

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3592

Use at peak throughput assumed, realistically need 3 x this, > 3 x?Powderhorns can cope re drive numbers (40/silo)…. But speed?

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

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2010

9940B

SAIT

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3592

3592b?

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

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• 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…