Using psradm to enable/disable a processor on Solaris
In multiprocessor environments, Solaris can allow enabling or disabling of processors. This although is not something that we would do all the time but can come handy when troubleshooting hardware issues.
Solaris has the psradm utility which allows enabling or disabling a Processor on the system. The psradm utility changes the operational status of processors. The legal states for the processor are on-line, offline, spare, Faulted, and no-intr. An online processor processes LWPs (lightweight processes) and can be interrupted by I/O devices in the system.
To enable or disable a processor on the system we need to know the Processor ID. This can be found using the psrinfo utility as follows:
# psrinfo 0 on-line since 17/03/2007 11:53:19
where 0 is the processor ID.
To know the path of the psradm command
# which psradm /usr/sbin/psradm
To disable a processor
# psradm -f 0
where '0’ is the processor ID and ‘-f' indicates the processor is taken offline (disable)
To enable a processor
# psradm -n 0
where '0’ is the processor ID and ‘-n' indicates the processor is brought online (enable)