Speaker
Describe the scientific/technical community and the scientific/technical activity using (planning to use) the EGEE infrastructure. A high-level description is needed (neither a detailed specialist report nor a list of references).
DIRAC (Distributed Infrastructure with Remote Agent Control) is
the Workload and Data
Management system (WMS) for the LHCb experiment. The DIRAC WMS
offers a transparent
way for LHCb users to submit jobs to the EGEE Grid as well as
local clusters and
individual PCs. This paper will describe workload management
optimizations which
ensure high job efficiency and minimized job start times.
With a forward look to future evolution, discuss the issues you have encountered (or that you expect) in using the EGEE infrastructure. Wherever possible, point out the experience limitations (both in terms of existing services or missing functionality)
The possibility of using generic VO Pilot Agents is very exciting
and DIRAC is ready
to exploit tools such as glexec in order to optimize workloads.
This would allow
DIRAC to work in a ‘filling’ mode by which multiple jobs may be
requested for
execution by Agents deployed to Grid Worker Nodes in a secure way.
Describe the added value of the Grid for the scientific/technical activity you (plan to) do on the Grid. This should include the scale of the activity and of the potential user community and the relevance for other scientific or business applications
The computing requirements of the LHCb experiment can only be
fulfilled through the
use of many distributed compute resources. DIRAC provides a
robust platform to run
data productions on all the resources available to LHCb
including the EGEE Grid.
More recently, user support was added to DIRAC that greatly
simplifies the procedure
of submitting, monitoring and retrieving output of Grid jobs for
the LHCb user
community.
Report on the experience (or the proposed activity). It would be very important to mention key services which are essential for the success of your activity on the EGEE infrastructure.
DIRAC submits Pilot Agents to the EGEE Grid via the gLite WMS as
normal jobs. Pilot
Agents then request jobs from the DIRAC Workload Management
System after the local
environment has been checked. Therefore DIRAC realizes the
so-called PULL paradigm
which ensures a high efficiency for LHCb Grid jobs.
