Format a disk 

• Any existing data will be destroyed when a disk is reformatted.

• The need for formatting a disk drive has dropped as more and more manufacturers ship their disk drives formatted and partitioned. You may not need to use the format utility when adding a disk drive to an existing system.

• If a disk has been relocated and is displaying a lot of disk errors, you can attempt to reformat it, which will automatically remap any bad sectors.

"How to Format a Disk"

Replace a system disk 

• Data from the damaged system disk must be restored from a backup medium; otherwise the system will have to be reinstalled by using the installation program.

Chapter 23, SPARC: Adding a Disk (Tasks) or Chapter 24, x86: Adding a Disk (Tasks) or if the system must be reinstalled, Solaris Advanced Installation Guide

Divide a disk into slices 

• Any existing data will be destroyed when a disk with existing slices is repartitioned and relabeled.

• Existing data must be copied to backup media before the disk is repartitioned and restored after the disk is relabeled.

Chapter 23, SPARC: Adding a Disk (Tasks) or Chapter 24, x86: Adding a Disk (Tasks)

Add a secondary disk to an existing system 

• Any existing data must be restored from backup media if the secondary disk is reformatted or repartitioned.

Chapter 23, SPARC: Adding a Disk (Tasks) or Chapter 24, x86: Adding a Disk (Tasks)

Repair a disk drive 

• Some customer sites prefer to replace rather than repair defective drives. If your site has a repair contract with the disk drive manufacturer, you may not need to use the format utility to repair disk drives.

• Repairing a disk drive usually means that a bad sector is added to a defect list. New controllers remap bad sectors automatically with no system interruption.

• If the system has an older controller, you may need to remap a bad sector and restore any lost data.

Chapter 25, The format Utility (Reference)