Speaker
Frank Glege
(CERN)
Description
CMS has chosen to use an online DB located at IP5
both for security reasons and to be able to take data
even without GPN connection.
The online DB (OMDS) is accessed by various applications for
data acquisition configuration (through OCI libraries via TStore),
detector slow control (via PVSS) and monitoring
via java or c++ libraries.
It also contains offline conditions data which are needed for high
level trigger
system which is running a simplified version of the event
reconstruction program on a cluster of few hundreds of machines.
A caching system based on Frontier allows to
reduce the load on the DB for this application similarly to what is
used in the offline DB.
A web based monitoring allows to display the run list and
most of the monitoring information. This tool makes use of caches
in order to reduce the load on the DB.
Many other applications rely on the DB: storage manager,
elog, access control packages.
Streaming is used to duplicate data for analysis
access via lxplus for the detector experts.
So far the OMDS has collected abut 1.5 TB of data per year.
Heavy use of the query optimization through appropriate indeces and
partitioning is used in the largest accounts.
Partitioning will allow archiving of old data if space limitation
or performance become an issue.
The experience with the online DB during 2010 data-taking is discussed and prospects for the future.
| Proposed speaker | Frank Glege |
|---|
Authors
Andreas Pfeiffer
(CERN)
Francesca Cavallari
(Univ. + INFN Roma 1)
Frank Glege
(CERN)
Mindaugas Janulis
(Vilnius University)
