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10.5 Understanding the Failure Degradation Mechanism

10.5 Understanding the Failure Degradation Mechanism
Releasing a component from the system when hardware fails is called degradation. Degradation cuts off access to that component, thereby preventing the problem in the system from being exacerbated.

The degradation scenarios are described below.
  1. Reserved degradation
    If degradation is not possible immediately at reboot or when a fatal error occurs, the degradation is reserved in the system to perform the degradation at the restart time. This scenario can be realized with the XSCF retaining the degradation location in memory.
  2. Degradation while Oracle Solaris is running
    CPUs, memory, etc. are degraded when they can be released while Oracle Solaris is running. Only the components allowed to be released while Oracle Solaris is running are subject to degradation.
  3. Degradation while POST is running
    A physical partition is degraded without being reset.
  4. Reserved degradation while OpenBoot PROM is running
    Degradation is reserved while OpenBoot PROM is running, and the degradation is performed after a reset. PCI adapter errors, memory errors, etc. are targets for degradation.
  5. Dynamic degradation of the internal paths in the hardware
    A lane is dynamically degraded in the paths between chassis, such as the SPARC M12/M10 chassis, crossbar units, and crossbar units in a crossbar box, and between components without resetting the system.
Use the showstatus command to display component degradation information. For details about managing failure degradation information, see "11.1.4 Checking Failed/Degraded Components."