Using RAIC for dependable on-line upgrading of distributed systems

The technology of redundant arrays of independent components (RAIC) uses groups of similar or identical distributed components to provide dependable services (Liu and Richardson, 2002). RAIC allows components in the redundant array to be added or removed dynamically during run-time. This paper gives a brief overview of RAIC and discusses its special application for dependable on-line upgrading of distributed systems. A proof-of-concept example is given to illustrate how problems that occur during upgrading can be masked by RAIC and thus not affect smooth operations of the system-under-upgrade.