Hardware System Availability

[C. Melgarejo]

[Originally Posted: 3/22/00-- Transferred by ReliaSoft Moderator]

I have a question for anyone who would bother to help me out. I want to calculate the availability of a proposed system. The system include servers, network equipment, other computers, etc.

Could you show me the method to do it?

Thanks

C. Melgarejo

[Crawford Smith]

[Originally Posted: 3/23/00-- Transferred by ReliaSoft Moderator]

Large system availability/maintainability can be determined via system simulation. A reliability block diagram (RBD) is constructed with each block representing a component in the system. Each block would contain the appropriate reliability and maintainability distribution information for the component. These blocks are then arranged reliabilitywise into a system form. Typically, this will be identical to how the components are arranged physically, although there are some exceptions to this rule of thumb. Unfortunately, there will probably not be a closed-form solution to the system availability. (The exception to this is for relatively systems with expontential failure and repair distributions. This requires the assumption that all of the components in the system have constant failure and repair rates, which is not often valid.) Since closed-form solutions are not readily available, simulation will then be required to determine the system availability. As I mentioned earlier, ReliaSoft's BlockSim provides this functionality in a flexible and easy-to-use format. A demo copy can be downloaded from this website.