Speaker
Dr
Benedetto Gorini
(CERN)
Description
This paper introduces the Log Service, developed at CERN within the ATLAS TDAQ/DCS
framework. This package remedies the long standing problem of attempting to direct
messages to the standard output and/or error in diskless nodes with no terminal. The
Log Service provides a centralized mechanism for archiving and retrieving qualified
information (Log Messages) created by TDAQ applications (Log Producers). One or
multiple Log Servers form the system’s archival container, based on the MySQL
database. A C++ interface is provided to access the Log Servers in a transparent
manner. Messages can be inserted, retrieved and/or removed. Furthermore, a user-
friendly web-based (PHP/HTML) tool is available to easily browse and/ore remove Log
Messages. The development of these software components are described in this paper.
Performance testing has been conducted within a controllable environment with up to
ten Log Producers, two Log Servers and two Log Managers. The outcome has been crucial
to identify the bottlenecks and constraints of the software and hardware
infrastructure. Especially important has been the need to limit the Web Server
connections to just one in order not to disturb the Log Message passing mechanism.
Author
Raul Murillo Garcia
(CERN)
