Author: Dworak, A.
Paper Title Page
WEMAU001 A Remote Tracing Facility for Distributed Systems 650
  • F. Ehm, A. Dworak
    CERN, Geneva, Switzerland
  Today the CERN's accelerator control system is built upon a large number of services mainly based on C++ and JAVA which produce log events. In such a largely distributed environment these log messages are essential for problem recognition and tracing. Tracing is therefore a vital part of operations, as understanding an issue in a subsystem means analyzing log events in an efficient and fast manner. At present 3150 device servers are deployed on 1600 diskless frontends and they send their log messages via the network to an in-house developed central server which, in turn, saves them to files. However, this solution is not able to provide several highly desired features and has performance limitations which led to the development of a new solution. The new distributed tracing facility fulfills these requirements by taking advantage of the Simple Text Orientated Message Protocol [STOMP] and ActiveMQ as the transport layer. The system not only allows to store critical log events centrally in files or in a database but also it allows other clients (e.g. graphical interfaces) to read the same events at the same time by using the provided JAVA API. This facility also ensures that each client receives only the log events of the desired level. Thanks to the ActiveMQ broker technology the system can easily be extended to clients implemented in other languages and it is highly scalable in terms of performance. Long running tests have shown that the system can handle up to 10.000 messages/second.  
slides icon Slides WEMAU001 [1.008 MB]  
poster icon Poster WEMAU001 [0.907 MB]  
FRBHMULT05 Middleware Trends and Market Leaders 2011 1334
  • A. Dworak, P. Charrue, F. Ehm, W. Sliwinski, M. Sobczak
    CERN, Geneva, Switzerland
  The Controls Middleware (CMW) project was launched over ten years ago. Its main goal was to unify middleware solutions used to operate CERN accelerators. An important part of the project, the equipment access library RDA, was based on CORBA, an unquestionable standard at the time. RDA became an operational and critical part of the infrastructure, yet the demanding run-time environment revealed some shortcomings of the system. Accumulation of fixes and workarounds led to unnecessary complexity. RDA became difficult to maintain and to extend. CORBA proved to be rather a cumbersome product than a panacea. Fortunately, many new transport frameworks appeared since then. They boasted a better design, and supported concepts that made them easy to use. Willing to profit from the new libraries, the CMW team updated user requirements, and in their terms investigated eventual CORBA substitutes. The process consisted of several phases: a review of middleware solutions belonging to different categories (e.g. data-centric, object-, and message-oriented) and their applicability to a communication model in RDA; evaluation of several market recognized products and promising start-ups; prototyping of typical communication scenarios; testing the libraries against exceptional situations and errors; verifying that mandatory performance constraints were met. Thanks to the performed investigation the team have selected a few libraries that suit their needs better than CORBA. Further prototyping will select the best candidate.  
slides icon Slides FRBHMULT05 [8.508 MB]