Speaker
Dr
Graeme Andrew Stewart
(CERN)
Description
ATLAS has recorded almost 5PB of RAW data since the LHC started
running at the end of 2009. Many more derived data products and
complimentary simulation data have also been produced by the
collaboration and, in total, 55PB is currently stored in the Worldwide
LHC Computing Grid by ATLAS. All of this data is managed by the ATLAS
Distributed Data Management system, called Don Quixote 2 (DQ2).
DQ2 has evolved rapidly to help ATLAS Computing operations to manage
these large quantities of data across the many grid sites at which
ATLAS runs and to help ATLAS physicists get access to this data. In
this paper we describe new and improved DQ2 services:
- Popularity service, which measures usage of data across ATLAS.
- Space monitoring and accounting at sites.
- Automated blacklisting service.
- Cleaning agents, which trigger deletion of unused data at sites.
- Deletion agents, to reliably delete unwanted data from sites.
We describe the experience of data management operation in ATLAS
computing, showing how these services enable management of petabyte
scale computing operations.
We illustrate the coupling of data management services to other parts
of the ATLAS computing infrastructure, in particular showing how
feedback from the distributed analysis system in ATLAS has enabled
dynamic placement of the most popular data, helping users and groups
to analyse the increasing data volumes on the grid.
Authors
Dr
Graeme Andrew Stewart
(CERN)
Dr
Vincent Garonne
(CERN)
