Solaris 10 systems on x86 architecture use the GNU GRand Unified Bootloader (GRUB) which is the boot loader responsible for loading a boot archive into a system's memory. The boot archive is a collection of critical files (kernel modules and configuration files) that are required to boot the Solaris OS. As stated in the Sun documentation:
These files are needed during system startup before the root file system is mounted. Two boot archives are maintained on a system:
- The boot archive that is used to boot the Solaris OS on a system. This boot archive is sometimes called the primary boot archive.
- The boot archive that is used for recovery when the primary boot archive is damaged. This boot archive starts the system without mounting the root file system. On the GRUB menu, this boot archive is called failsafe. The archive's essential purpose is to regenerate the primary boot archive, which is usually used to boot the system.
The Solaris OS generally keeps the boot archive properly synchronized on
its own. Sometimes, the boot archive gets corrupted--for example when
(bad) patches are applied, or the the operating system crashed. In these
cases, the boot archive must be regenerated. This is easily accomplished
following the Sun documentations x86: How to Boot the Failsafe Archive
and x86: How to Boot the Failsafe Archive to Forcibly Update a Corrupt
The main drawback is when the system is encapsulated under a SVM mirror
(RAID-1) since the
md driver is not managed under the failsafe mode.
Please refer to this blog
on this subject, if needed.