If the system is attached to a network, the test machine can be added as a client of a server. If a problem occurs, the system can be booted from the network. The local disks can then be mounted, and any fixes can be made. Alternatively, the system can be booted directly from the Solaris system CD-ROM.
Another way to recover from disaster is to have another bootable root file system. Use format(1M) to make a partition that is the exact size of the original. Then use dd(1M) to copy the bootable root file system. After making a copy, run fsck(1M) on the new file system to ensure its integrity.
Subsequently, if the system cannot boot from the original root partition, boot the backup partition. Use dd(1M) to copy the backup partition onto the original partition. You might have a situation where the system cannot boot even though the root file system is undamaged. For example, the damage might be limited to the boot block or the boot program. In such a case, you can boot from the backup partition with the ask (-a) option. You can then specify the original file system as the root file system.