Fault-tolerant PACS server design and evaluation

Abstract

A single point of hardware failure in picture archiving and communication system (PACS) is at the PACS controller, or the main archive server. When it occurs, it renders the entire PACS inoperable and crippled until the problem is diagnosed and resolved. Many current PACS do not have a fault-tolerant design or adequate backup system for the main archive server due to several issues including cost. This paper describes a novel, portable, and scalable fault-tolerant PACS controller design that is affordable for most PACS implementations. Currently, most PACS controllers are based on UNIX servers. The UNIX server can be replaced by a specially designed Continuous Availability Server (CAS) consisting of three identical machines as the UNIX server that run the same operating system and application software simultaneously and independently. Hardware failure of any one or multiple components in a machine in the CAS, including the power supply, processors, SCSI ports, network ports, RAID controller, and disk controllers, was simulated. A series of clinical scenarios were performed while executing a simulated failure of the key hardware components within the CAS. No interruption of PACS data flow passing through the CAS was observed. Therefore, the result is a continuous availability server immune to a single point of hardware failure.