x86: Introducing Fast Reboot

This feature is available, starting with build 100 of the Solaris Express Community Edition release, and in the OpenSolaris 2008.11 OS.

Fast Reboot implements an in-kernel boot loader that loads the kernel into memory, then switches to that kernel, thus enabling the reboot process to occur within seconds. With Fast Reboot, you can reboot to a new kernel without experiencing the long delays that can be imposed by the BIOS and boot loader. The ability to fast reboot a system drastically reduces down time and improves efficiency.

Note - Fast Reboot is currently not available on the SPARC platform.

The following sections provide a general overview of the Fast Reboot feature. For task related information, see Using Fast Reboot on the x86 Platform (Task Map).

Modifications to the `reboot` Command to Support Fast Reboot

To support Fast Reboot, the reboot command has been modified to include two new options:

-f

Initiates the fast reboot process, when used with the reboot command.

-e

Initiates a fast reboot to an alternate boot environment (BE), when used in conjunction with the -f option,

Note - The -e option cannot be used to fast reboot to an alternate BE in the OpenSolaris 2008.11 release. For instructions on initiating a fast reboot to an alternate BE in this release, see x86: Initiating a Fast Reboot to an Alternate Boot Environment in the OpenSolaris 2008.11 OS.

For more information, see the reboot(1M) man page.

Implementation of the `quiesce` Function

The system's capability to bypass the firmware when booting a new OS image has dependencies on device drivers' implementation of a new device operation entry point, quiesce. On supported drivers, this implementation quiesces a device, so that at completion of the function, the driver no longer generates interrupts or access memory. This implementation also resets the device to a hardware state, from which the device can be correctly configured by the driver's attach routine, without a power cycle of the system or being configured by the firmware. For more information about this functionality, see the quiesce(9E) and dev_ops(9S) man pages.

Note - Not all device drivers implement the quiesce function. For troubleshooting instructions, see x86: Troubleshooting Conditions That Might Prevent Fast Reboot From Working.

New `uadmin` Function

Other changes that support Fast Reboot on the x86 platform include the new uadmin function, AD_FASTREBOOT. This function resets the system, enabling the reboot command to bypass the BIOS and the boot loader phases.

Note - The uadmin 2 8 command has limited functionality. If the command is used to facilitate a fast reboot of the system, neither the boot archive, nor the menu.lst file are updated. For this reason, the reboot -f command is the preferred method for initiating a fast reboot.

For more information, see the uadmin(2)man page.