Tuesday, March 17, 2015

Solaris 11: Activate FASTREBOOT to significantly reduce boot time


The Fast Reboot feature of Oracle Solaris 11 is supported on both SPARC and x86 platforms. The Fast Reboot feature implements an in-kernel boot loader that loads the kernel into memory and then switches to that kernel, so that the reboot process occurs within seconds.

For x86 systems:

Fast reboot, bypassing firmware and boot loader. The new kernel will be loaded into memory by the running kernel, and control will be transferred to the newly loaded kernel. If disk or kernel arguments are specified, they must be specified before other boot arguments.

For SPARC systems:

Speeds up rebooting by skipping some POST tests.

The Fast Reboot feature is controlled by SMF and implemented through a boot configuration service, svc:/system/boot-config. The boot-config service provides a means for setting or changing the default boot parameters.

The fastreboot_default property of the boot-config service enables an automatic fast reboot of the system when either the reboot or the init 6 command is used. When the config/fastreboot_default property is set to true, the system automatically performs a fast reboot, without the need to use the reboot -f command. By default, this property's value is set to true on an x86 based system and false on a SPARC based system.

 The svc:/system/boot-config:default service consists of the following properties:

   config/fastreboot_default
   config/fastreboot_onpanic
These properties can be configured by using the svccfg and svcadm commands.

For example, to disable the default behavior of the fastreboot_onpanic property on an x86 based system, you would set the property's value to false, as shown here:

# svccfg -s "system/boot-config:default" setprop config/fastreboot_onpanic=false
# svcadm refresh svc:/system/boot-config:default
Changing one property's value does not affect the default behavior of the other property.

The following example shows how to make a fast reboot the default behavior on a SPARC based system by setting the boot-config SMF service property to true.

# svccfg -s "system/boot-config:default" setprop config/fastreboot_default=true
# svcadm refresh svc:/system/boot-config:default
Setting the property's value to true accelerates the reboot process, which enables systems that support the Fast Reboot feature to bypass certain POST tests. When the property is set to true, you can perform a fast reboot of the system without having to use the -f option with the reboot command.

To reboot a system that has the Fast Reboot feature enabled, without reconfiguring the boot-config service to disable the feature, use the -p option with the reboot command, as shown here:

# reboot -p

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