Strategies for Fault-Tolerant Computing For Window…….ppt

Strategies for Fault-Tolerant ComputingFor Windows Server 2003 Mehmet Altan A?IKG?Z Ercan SARA? Agenda Introduction Fault-tolerant servers Fault tolerance on Windows Unique Benefits Clustering Comparison of Clusters Stratus ftServer FtServer Software Availability Summary Introduction Availability the percentage of time that a system is capable of serving its intended function. Correlation Between Availability and Annual Downtime Importance of Availability Availability of mission-critical information systems is often tied directly to business performance or revenue Average Cost of Unplanned Downtime for Various Industries The Availability Equation: People, Process, and Technology Fault-Tolerant Servers minimizing causes of downtime is through the use of fault-tolerant servers, combined with software that supports them If a primary component fails, the secondary component takes over in a process that is seamless to the application running on the server. Fault-Tolerant Servers Most high-end servers employ at least some redundant components to eliminate common points of failure but they will still fail when a nonredundant component such as a microprocessor or memory controller fails True fault-tolerant servers, however, employ complete redundancy across all system components, ensuring that no single point of failure can compromise system availability. Traditional Barriers to Adoption Extremely high hardware costs The typical cost for an entry-level fault-tolerant server running a proprietary operating system was $250,000 prior to 2000 Complexity and expense of writing software Writing programs for these systems required a deep understanding of transactional semantics and manual “checkpointing” at the application level Fault Tolerance on Windows Microsoft designed the Windows Server 2003, Enterprise Edition, operating system to fully support fault-tolerant servers Specific enhancements in Windows Server 2003 that apply to fault-tolerant servers