CERN [email protected] december-00 La Politique du tout PC au CERN Séminaire EDF Clamart – 15...
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Transcript of CERN [email protected] december-00 La Politique du tout PC au CERN Séminaire EDF Clamart – 15...
CERN
[email protected] december-00
La Politique du tout PC au CERNLa Politique du tout PC au CERN
Séminaire EDF
Clamart – 15 décembre 2000
Les Robertson
CERN/IT – Genève
CERN
december-00 - #2les robertson - cern/it
SommaireSommaire
Le problème La stratégie Les difficultés
CERN
december-00 - #4les robertson - cern/it
Architectures & operating systems supported at end 1999
AIX
Windows NT
Irix
Sola
ris
Digital Unix
HP-
UXM
AC-
OS
Linu
x
Windows
95
SPARCMIPS
Inte
l IA-3
2
PA-RISCPower
PC
Alpha Windows 2000The legacy of ten yearsThe legacy of ten years
of RISC computingof RISC computing
CERN
december-00 - #5les robertson - cern/it
Combien d’architectures et systèmes d’exploitation sont vraiment nécessaire?
Combien coûte le support? Combien vaut la diversité?
Comment imposer des limitations de choix dans un environnement de recherche scientifique ?
L’Organisation Européenne pour la Recherche Nucléaire
20 pays européens
2,700 employées
6,000 utilisateurs
CERN
CERN
december-00 - #7les robertson - cern/it
The Large Hadron Collider - LHCThe Large Hadron Collider - LHC
LHC accelerator under construction Proton-proton collider 27 km of super-conducting magnets Target date for first beams - 2005 Four experiments
Example - CMS 2000 physicists, 150 universities
The LHC DetectorsCMS
ATLAS
LHCb3.5 PetaBytes / year
~108 events/year
CERN
december-00 - #9les robertson - cern/it
HEP Computing CharacteristicsHEP Computing Characteristics
Large numbers of independent events trivial parallelism
Large data sets smallish records mostly read-only
Modest I/O rates few MB/sec per fast processor
Modest floating point requirement SPECint performance
High Througput Computing
Very large aggregate requirements – computation, data• Scaling up is not just big – it is also complex
• …and once you exceed the capabilities of a single geographical installation ………?
network servers
tape servers
disk servers
application servers
Generic computing farm
Cern/it/pdp-les.robertson 10-98-10 les.
rob
ert
son
@ce
rn.c
h
Estimated CPU Capacity at CERN
0
500
1,000
1,500
2,000
2,500
1998 1999 2000 2001 2002 2003 2004 2005 2006
year
K S
I95
~10K SI951200 processors
Non-LHC
Moore’s Law – estimate of the capacity for fixed level of investment, fixed number
of processors
LHC
10-20Kcpus?
network servers
tape servers
disk servers
application servers
Generic computing farm
Cern/it/pdp-les.robertson 10-98-12 les.
rob
ert
son
@ce
rn.c
h
LHC physics facility – 4 experiments
2 M SPECint9510-20K processors
2 PByte disk>20 K disks
CERN
december-00 - #13les robertson - cern/it
Summary of the problemSummary of the problem
HEP is using far too many operating systems in many cases with only slightly different functionality or hardware
cost benefits and at a high cost for users and support teams
The scale of LHC computing - massive numbers of processors/boxes integration of regional computing centres and CERN
problem is how to manage on this scale while limiting costs of equipment, management &
support
We must reduce the diversity while retaining flexibility to use low-cost, mass market componentsand adapt rapidly to changing physics needs
CERN
december-00 - #15les robertson - cern/it
OpportunityOpportunity
PCs + { Linux ¦ Windows } offer an historic opportunity to reduce the solution set
Costs and performance PCs will consistently be among the very best
price/performers for HEP codes They may not be the fastest,but they are fast
enough
Linux -a non-proprietary operating system compatible with the recent Unix history
Windows – a mass market alternative – widely used on the desktop
CERN
december-00 - #16les robertson - cern/it
PolicyPolicy
Restrict ourselves to PC hardware with Linux or Windows 2000
Develop a migration plan - progressively freeze support for other Unixes,
announcing end-dates which are reasonable for old experiments,
strongly discourage further investments in RISC systems by current and future experiments
install large Linux public facility, testbed for future experiments
Concentrate investment in Linux and Windows bring support up to the standards of proprietary
Unixes tackle the problems of scaling the management
and performance of physics farms and desktops seek HEP-wide consensus
CERN
december-00 - #17les robertson - cern/it
But do not be unrealistic ----But do not be unrealistic ----
This is a convergence policy which looks realistic now and will provide a single starting point
for LHC computing but we can be sure that the industry
will not stand still, and we shall sooner or later have to expand the systems and architectures supported
AIX
WNTIrix
Sola
ris
Digital Unix
HP-
UX
MAC-
OS
Linu
x
Windows
95
SPARC
MIPS In
tel I
A-32
PA-RISC
Power
PC
Alpha LinuxWindows
2000
Intel IA-64- - - ?
CERN
[email protected] december-00
Les difficultésLes difficultés et l'état de la migrationet l'état de la migration
CERN
december-00 - #19les robertson - cern/it
Difficulties - IDifficulties - I
Physics – (almost) entirely Unix based Linux is not quite ready
(Too) wide a choice of kernels, compilers, debuggers Different versions supported by different applications Some applications not supported on Linux Complex packages (Oracle, AFS) – better go with the
standard platform Stability problems under load Who provides in-depth, on-site Linux systems support?
Solution: Standard Linux Package certified for all CERN
applications Solaris/SPARC for special purposes Open posts for Linux experts
CERN
december-00 - #20les robertson - cern/it
Difficulties - IIDifficulties - II
In a research environment Easy to estimate the costs of systems support Hard to estimate the cost of application migration
The application experts have already moved on The developers have other (more interesting)
problems to solve The problem is not only to port the code but (more important) to acquire confidence in the
physics results Compiler, architecture, old bugs But there are signs that Linux+Intel are as good as
any! In the past, the production use of multiple
architectures was an important factor in finding bugs
CERN
december-00 - #21les robertson - cern/it
Current Status – PhysicsCurrent Status – Physics
For older experiments – Strong resistance to aggressive migration
proposal Agreement for complete freeze on all proprietary
Unixes during 2003
For future experiments (not yet collecting data) – General agreement on Linux/Intel for production,
but require a second (limited) development platform for validation
For new experiments collecting data now Easy to calculate the benefits Have already completed migration
CERN
december-00 - #22les robertson - cern/it
Current Status – other applicationsCurrent Status – other applications
Desktop applications Web, Office, …. Windows 2000
Engineering applications Aggressive migration plan to Windows NT/2000 &
Linux, with some residual SUN Major exception is mechanical CAE (Euclid + Digital
Unix)
Administration Database (Oracle) on SUN Clients Web-based (Outlook/Netscape) Strong pockets of MAC resistance
– led by the Directorate
CERN
december-00 - #23les robertson - cern/it
ConclusionsConclusions
Les besoins énormes du LHC exigent la standardisation et l’utilisation des composants bon-marché
Opportunité –Linux + Windows 2000 avec Intel IA32/64 & Ethernet
Grande inertie (résistance?) de la part des « vielles » expériences - il faudra 4 années pour terminer la migration
Mais – déjà plus de trois quarts des systèmes installés et 90% de la capacité sont Linux/Intel