GridPP: the UK's contribution to the international collaboration
building a worldwide Grid, the LHC Computing Grid
GridPP – is the system usable?
Tony Doyle
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
Summary• GridPP runs a major part of the EGEE/LCG
Grid, which supports ~3000 users • The Grid is not (yet) as transparent as end-
users want it to be• The underlying overall failure rate is ~10%• User (interface)s, middleware and operational
procedures (need to) adapt• (see talks by Dave Britton and Stephen Burke
for more info. on performance and operations [now])
• Procedures to manage the underlying problems such that system is usable are highlighted
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
5 million hours
“Active” User requires thousands of CPU hoursEGEE CPU hours(1 April 2006 to 31 July
2006 )
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
Virtual Organisations• Users are grouped into Virtual Organisations
– Users/VO varies from 1 to 806 members (and growing..)
• Broadly four classes of VO– LHC experiments– EGEE supported– Worldwide (mainly non-LHC particle physics)– Local/regional e.g. UK PhenoGrid
• Sites can choose which VOs to support, subject to MOU/funding commitments– Most GridPP sites support ~20 VOs– GridPP nominally allocates 1% of resources to EGEE non-HEP
VOs– GridPP currently contributes 30% of the EGEE CPU resources
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
User View?• Perspective matters• This talk is not
– a usability survey– unbiased– representative
• Straw poll – users overcame initial
registration hurdles within ~two weeks
– users adapt to Grid in (un-)coordinated ways
– The Grid was sufficiently flexible for many analysis applications
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
Physics AnalysisESD: Data or Monte CarloESD: Data or Monte Carlo
Event Tags Event TagsEvent Selection
Analysis Object DataAnalysis Object DataAnalysis Object DataAnalysis Object DataAnalysis Object Data
AOD
Analysis Object Data
AOD
Calibration DataCalibration Data
Analysis, Skims
Raw DataRaw Data
Collaboration
-wide
Tasks
Analysis
Groups
Individual
PhysicistsPhysics Analysis
Physics
Objects Physics
Objects
Physics
Objects
INC
RE
AS
ING
DA
TA
FLO
W
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
User evolution
Number of UK Grid users (exc. Deployment Team)Quarter: 05Q4 06Q2 06Q3Value: 1342 1831 2777
Many EGEE VOs supported c.f. 3000 EGEE targetNumber of active users (> 10 jobs per month)Quarter: 05Q4 06Q1 06Q2Value: 83 166 201Fraction: 6.2% 11.0%Viewpoint: growing fairly rapidly, but not as active
as they could be? depends on the “active” definition
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
806 atlas 763 dzero 577 cms 566 dteam 150 lhcb 131
alice 75 bio 65 dteamsgm 41 esr 31 ilc 27 atlassgm 27 alicesgm 21 cmsprg 18
atlasprg 17 fusn 15 zeus 13 dteamprg 13 cmssgm 11 hone 9 pheno 9 geant 7 babar 6 aliceprg 5 lhcbsgm 5 biosgm 3 babarsgm 2 zeussgm 2 t2k 2 geantsgm 2 cedar 1 phenosgm
1 minossgm 1 lhcbprg 1 ilcsgm 1 honesgm 1 cdf
Kn
ow
you
r users
? U
K-e
nab
led
VO
s
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
User Interface
• The GUI is relatively low-level (jobs, file collections)• Dynamic panels for higher level functions
Job details
Logical
Folders
Job Monitoring
Log window
Job builder
Scriptor
Screenshot of the Ganga GUI
Screenshot of the Ganga GUI
Dockable windows
Dockable windows
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
Complex ApplicationsATLAS• GANGA software framework (jointly with LHCb)• data challenges• producing Monte Carlo data •10 million CPU hours
per year
CMS• Monte Carlo production, data transfer, job submission• CMS transfers top a petabyte a month for the last three months
LHCb• DIRAC software to submit analysis jobs using Grid• 2006 analysis job completion efficiency improved to 91%
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
WLCG MoU• Particle physicists collaborate,
play roles and delegate – e.g. “prg” production group
“sgm” software group managers
• Underpinned by Memoranda of Understanding
• Current MoU signatories:China France Germany Italy India Japan Netherlands Pakistan Portugal Romania Taiwan UK USA
• Pending signatures: Australia Belgium Canada Czech Republic Nordic Poland Russia Spain Switzerland Ukraine
• Negotiation w.r.t. resource and service level
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
Resource allocation• Need to assign quotas and priorities to VOs and measure delivery
• VOMS provides group/role information in the proxy
• Tools to control quotas and priorities in site services being developed– So far only at whole-VO level– Maui batch scheduler is flexible, easy to map to groups/roles– Sites set the target shares– Can publish VO/group-specific values in GLUE schema, hence the RB
can use them for scheduling
• Accounting tool (APEL) measures CPU use at global level (UK task)– Storage accounting currently being added– GridPP monitors storage across UK– Privacy issues around user-level accounting, being solved by
encryption
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
User Support• Becoming vital as the number of users grows
– But modest effort available in the various projects
• Global Grid User Support (GGUS) portal at Karlsruhe provides a central ticket interface– Problems are categorised
• Tickets are classified by an on-duty Ticket Process Manager, and assigned to an appropriate support unit– UK (GridPP) contributes support effort
• GGUS has a web-service interface to ticketing systems at each ROC– Other support units are local mailing lists– Mostly best-effort support, working hours only
• Currently ~tens of tickets/week– Manageable, but may not scale much further– Some tickets slip through the net
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
Documentation & Training
• Need documentation and training for both system managers and users– Mostly expert users up to now, but user community is expanding– Induction of new VOs is a particular problem – no peer support– EGEE is running User Fora for users to share experience
• Next in Manchester in May ’07 (with OGF)– EGEE has a dedicated training activity run by NeSC/Edinburgh
• Documentation is often a low priority, little dedicated effort– The rapid pace of change means that material requires constant
review• Effort on documentation is now increasing
– GridPP has appointed a documentation officer• GridPP web site, wiki
– Installation manual for admins is good• There is also a wiki for admins to share experience
– Focus is now on user documentation• New EGEE web site – coming soon
Usable Systems21 September 2006
Tony Doyle - University of Glasgow
Alternative view?
• The number of users in the Grid School for the Gifted is ~manageable now
• The system may be too complex, requiring too much work by the “average user”?
• Or the (virtual) help desk may not be enough?
• Or the documentation may be misleading?
• Or..• Having smart users helps
(the current ones are)