During boot time, the service processor does not configure processors or memory DIMMs that are marked“bad.”If a processor or memory DIMM is deconfigured, the processor or memory DIMM remains offline forsubsequent reboots until it is replaced or repeat gard is disabled. The repeat gard function also providesthe user with the option of manually deconfiguring a processor or memory DIMM, or re-enabling apreviously deconfigured processor or memory DIMM.For information about configuring or deconfiguring a processor, see the ProcessorConfiguration/Deconfiguration Menu on page 41. For information about configuring or deconfiguring amemory DIMM, see the Memory Configuration/Deconfiguration Menu on page 42. Both of these menusare submenus under the System Information Menu. You can enable or disable CPU Repeat Gard orMemory Repeat Gard using the Processor Configuration/Deconfiguration Menu.Run-Time CPU Deconfiguration (CPU Gard)L1 instruction cache recoverable errors, L1 data cache correctable errors, and L2 cache correctable errorsare monitored by the processor run-time diagnostics (PRD) code running in the service processor. When apredefined error threshold is met, an error log with warning severity and threshold exceeded status isreturned to AIX. At the same time, PRD marks the CPU for deconfiguration at the next boot. AIX willattempt to migrate all resources associated with that processor to another processor and then stop thedefective processor.Service Processor System Monitoring - SurveillanceSurveillance is a function in which the service processor monitors the system, and the system monitors theservice processor. This monitoring is accomplished by periodic samplings called heartbeats.Surveillance is available during the following phases:v System firmware bringup (automatic)v Operating system run-time (optional)Note: Operating system surveillance is disabled in partitioned systems.System Firmware SurveillanceSystem firmware surveillance is automatically enabled during system power-on. It cannot be disabled bythe user, and the surveillance interval and surveillance delay cannot be changed by the user.If the service processor detects no heartbeats during system IPL (for a set period of time), it cycles thesystem power to attempt a reboot. The maximum number of retries is set from the service processormenus. If the fail condition persists, the service processor leaves the machine powered on, logs an error,and displays menus to the user. If Call-out is enabled, the service processor calls to report the failure anddisplays the operating-system surveillance failure code on the operator panel.Chapter 4. Using the Service Processor 59
