When you install Oracle Solaris OS on a system, the bootadm command creates one primary boot archive and one failsafe archive.
A primary boot archive is a subset of a root (/) file system. This boot archive contains all of the kernel modules, driver.conf files, and some configuration files. These files are located in the /etc directory. The files in the boot archive are read by the kernel before the root (/) file system is mounted. After the root (/) file system is mounted, the boot archive is discarded by the kernel from memory. Then, file I/O is performed against the root device.
The files that make up the SPARC boot archives are located in the /platform directory.
The contents of this directory are divided into three groups of files:
Files that are required for a sun4u boot archive
Files that are required for a sun4v boot archive
Files that are required for a sun4us boot archive
The files that make up the x86 boot archives are located in the /platform/i86pc directory.
To list the files and directories that are included in the boot archives, use the bootadm list-archive command.
If any files in the archive are updated, the boot archive must be rebuilt. For modifications to take effect, the rebuild of the archive must take place before the next system reboot.
The failsafe boot archive is the second type of archive that is created when you install the Solaris OS.
A failsafe boot archive has the following benefits and characteristics:
Can boot on its own
Is created by default during installation of the OS
Requires no maintenance