Abstract :
Despite the most careful planning, system applications can be dogged by unexpected failures. Our firm is keenly aware of the need for availability. To help meet that need, I developed an experimental CORBA-based restart service and monitor called Piranha, which both monitors and manages distributed applications to help systems attain high availability. First, Piranha acts as a network monitor that reports failures through a graphical user interface. Second, Piranha acts as a manager: it automatically restarts failed CORBA objects, replicates stateful objects (objects that maintain an internal set of values) on-the-fly, migrates objects from one host to another and enforces predefined replication degrees-numbers of copies-on groups of objects. As a backdrop to the discussion of Piranha´s design and implementation, this article first examines the ways in which a CORBA ORB should support availability. I then explain how Piranha affords availability
Keywords :
distributed processing; fault diagnosis; fault tolerant computing; object-oriented methods; reliability; starting; system monitoring; system recovery; CORBA tool; Piranha; copy number; distributed applications; graphical user interface; internal value set; network monitor; object groups; object migration; object request brokers; predefined replication degree enforcement; restart service; stateful object replication; systems availability; unexpected failure reporting; Application software; Availability; Computerized monitoring; Condition monitoring; Hardware; Object detection; Operating systems; Programming profession; Real time systems; Satellites;
