Speakers
Dr
David Colling
(Imperial College London)Dr
Olivier van der Aa
(Imperial College London)
Description
The LCG [1] have adopted a hierarchical Grid computing model which has a Tier 0
centre at CERN, national Tier 1 centres and regional Tier 2 centres. The roles of the
different Tier centres are described in the LCG Technical Design Report [2] and the
levels of service required from each level of Tier centre is described in the LCG
Memorandum of Understanding [3] . Many of the Tier 2 centres are formed by federating
the resources belonging to geographically distributed institutes in a given region.
The institutes within such a federation are able provide different levels of
resources and typically will have different levels of expertise. Providing a good
level of service in such situations is challenging. In this context, the London Tier2
(LT2) [4] is one of the four federated Tier 2 centres within the GridPP [5]
collaboration in UK. The LT2 is distributed between five institutes in the London
area and currently totals around 1 Mega Spec Int 2000 [6] . In this paper we analyze
how we can minimize the time to solve LT2 failures within the constraint of the
available human resources and their mobility. The analysis takes into account, the
time to travel between institutes, the type of problems each support person can solve
and their availability. We demonstrate how to create a hierarchy of support staff to
solve an identified problem. We also provide an estimate of time to solve for future
LT2 failures. This is based on failures rates extracted from the monitoring
information and known response times. We suggest this failure management method as a
model for any distributed Tier2.
[1] LCG http://lcg.web.cern.ch/LCG/
[2] LHC Computing Grid, Technical Design Report, LCG-TDR-001, CERN-LHCC-2005-024.
[3] http://lcg.web.cern.ch/LCG/C-RRB/MoU/LCG_T0-2_draft_final_051012.pdf
[4] LT2, http://www.gridpp.ac.uk/tier2/london/
[5] GridPP, UK computing for particle physics http://www.gridpp.ac.uk/
[6] Spec Int 2000 http://www.spec.org/cpu2000/
Primary authors
Dr
Alex Martin
(Queen Mary, University of London)
Ms
Alice Fage
(University College London)
Dr
Ben Waugh
(University College London)
Dr
David Colling
(Imperial College London)
Mr
David McBride
(Imperial College London)
Dr
Gianfranco Sciacca
(University College London)
Dr
Giuseppe Mazza
(Queen Mary, University of London)
Dr
Grigori Rybkine
(Royal Holloway, University of London)
Dr
Henry Nebrensky
(Brunel University)
Mrs
Mona Aggarwal
(Imperial College London)
Dr
Olivier van der Aa
(Imperial College London)
Dr
Paul Kyberd
(Brunel University)
Dr
Rand Duncan
(Brunel University)
Dr
Simon George
(Royal Holloway, University of London)
Dr
William Hay
(University College London)
