Objectivity/Corba distributed database performance on a gigabit Sun-ultra-10 cluster

Dynacore´s project objective is to provide tools for the remote operation of large physics experiments. Our group concentrates on the design of a remote control room for the Textor-94 plasma-physics experiment, which will incorporate a distributed database, accessible with Corba over Internet. During normal operation, Textor-94 generates hundreds of megabytes of measurement data within the few seconds of a plasma shot. These shots are generated approximately every ten minutes, in total around 30 shots per day. A database will make the measurement data available to scientists, both at the experiment and in remote control rooms, which can be located in different countries, within minutes after the acquisition. Fast access to the database and a high data-storage speed are, therefore, of utmost importance. We have defined a set of data objects, which allow storage of virtually any kind of Textor measurement data. An Objectivity object-oriented database is used to store these objects. We have also designed an architecture in which database clients access the measurement database solely via data managers with Corba-interfaces. The data managers introduce security into the database, and also hide details of the database implementation for the users. An object manager provides clients with a central starting point, and distributes the total database load in an intelligent way over all available data-managers