Providing Open Architecture High Availability Solutions

5.6.4 Approach

Systems are comprised of a broad range of components that need to be upgraded, including

hardware, operating systems, applications and peripherals. In systems designed for service

availability, many of these components are redundant. This enables the system to transfer operation

away from the component that needs to be upgraded without any outage to the service.

5.6.5 Techniques

Hardware upgrades require the ability for components to be removed from and inserted into the

system without requiring a reboot or the system to be powered down. This capability is called hot-

swap and is a major feature of new platforms such as CompactPCI. Hot-Swap requires hardware

and operating system support to enable the capability.

Operating systems and other software components can either be dynamically upgraded during

operation, or the system can transfer operation to a standby component to enable the upgrade to

occur off-line.

5.6.6 Dependencies

In-service upgrading depends on essentially the same functions as repair. All components that need

to be upgraded while the system is service must have the ability to be hot-swapped in and out of the

system. In the case of hardware, the software associated with that hardware must also be capable of

being dynamically loaded and unloaded.