Table of Contents
Advertisement
When the system watchdog is running, a system hang, or more specifically, the hang
of the clock interrupt handler, causes an expiration.
The system watchdog mode is the default. If the application watchdog is not
initialized, then the system watchdog mode is used.
The application mode enables you to:
Configure the watchdog timer – Your applications running on the host can
■
configure and use the watchdog timer, enabling you to detect fatal problems from
applications and to recover automatically.
Program Alarm3 – This capability enables you to generate this alarm in case of
■
critical problems in your applications.
The setupsc command, an existing command for the ALOM CMT compatability
CLI (in ILOM), can be used to configure the recovery for the system watchdog only:
sc> setupsc
The recovery configuration for the application watchdog is set using input/output
control codes (IOCTLs) that are issued to the ntwdt driver.
Watchdog Timer Limitations
The limitations of the watchdog timer mode include:
In the case of the watchdog timer expiration detected by the system controller, the
■
recovery is attempted only once. There are no further attempts of recovery if the
first attempt fails to recover the domain.
If the application watchdog is enabled and you break into the OpenBoot PROM
■
by issuing the break command from the system controller's sc> prompt, the
system controller automatically disables the watchdog timer.
Note – The system controller displays a console message as a reminder that the
watchdog, from the system controller's perspective, is disabled.
However, when you re-enter the Solaris OS, the watchdog timer is still enabled
from the Solaris OS perspective. To have both the system controller and the
Solaris OS view the same watchdog state, you must use the watchdog application
to either enable or disable the watchdog.
If you perform a dynamic reconfiguration (DR) operation in which a system
■
board containing kernel (permanent) memory is deleted, then you must disable
the watchdog timer's application mode before the DR operation and enable it
after the DR operation. This is required because Solaris software quiesces all
76
Sun Netra T5440 Server Administration Guide • April 2010
Advertisement
Table of Contents
