Managing Disks (Overview)

This chapter provides overview information about Solaris disk slices and introduces the format utility.

This is a list of overview information in this chapter.

• What's New in Disk Management in the Solaris 9 Update Releases?

• What's New in Disk Management in the Solaris 9 Release?

• Where to Find Disk Management Tasks

• Overview of Disk Management

• Disk Terminology

• About Disk Slices

• The format Utility

• About Disk Labels

• Dividing a Disk Into Slices

For instructions on how to add a disk to your system, see Chapter 34, SPARC: Adding a Disk (Tasks) or Chapter 35, x86: Adding a Disk (Tasks).

What's New in Disk Management in the Solaris 9 Update Releases?

This section describes a new disk management feature in this Solaris release.

SPARC: Multiterabyte Volume Support With EFI Disk Label

Solaris 9 4/03 - This Solaris release provides support for disks that are larger than 1 terabyte on systems running a 64-bit Solaris kernel. The Extensible Firmware Interface (EFI) disk label is not available for disks connected to a system running a 32-bit Solaris kernel, such as a system running the Solaris x86 Platform Edition.

You can download the EFI specification at http://www.intel.com/technology/efi/main_specification.htm.

The EFI label provides support for physical disks and virtual disk volumes. This release also includes updated disk utilities for managing disks greater than 1 terabyte. The UFS file system is compatible with the EFI disk label, and you can create a UFS file system greater than 1 terabyte. For information on creating a multiterabyte UFS file system, see SPARC: Support of Multiterabyte UFS File Systems.

The unbundled Sun QFS file system is also available if you need to create file systems greater than 1 terabyte. For information on the Sun QFS file system, see http://docs.sun.com/db/doc/816-2542-10.

The Solaris Volume Manager software can also be used to manage disks greater than 1 terabyte in this Solaris release. For information on using Solaris Volume Manager, see Solaris Volume Manager Administration Guide.

The VTOC label is still available for disks less than 1 terabyte in size. If you are only using disks smaller than 1 terabyte on your systems, managing disks will be the same as in previous Solaris releases. In addition, you can use the format-e command to label a disk less than 1 terabyte with an EFI label. For more information, see Example--Labeling a Disk Less Than 1 Terabyte with an EFI Label.

Comparison of the EFI Label and the VTOC Label

The EFI disk label differs from the VTOC disk label in the following ways:

• Provides support for disks greater than 1 terabyte in size.

• Provides usable slices 0-6, where slice 2 is just another slice.

• Partitions (or slices) cannot overlap with the primary or backup label, nor with any other partitions. The size of the EFI label is usually 34 sectors, so partitions start at sector 34. This feature means no partition can start at sector zero (0).

• No cylinder, head, or sector information is stored in the label. Sizes are reported in blocks.

• Information that was stored in the alternate cylinders area, the last two cylinders of the disk, is now stored in slice 8.

• If you use the format utility to change partition sizes, the unassigned partition tag is assigned to partitions with sizes equal to zero. By default, the format utility assigns the usr partition tag to any partition with a size greater than zero. You can use the partition change menu to reassign partition tags after the partitions are changed. However, you cannot change a partition with a non-zero size to the unassigned partition tag.

Restrictions of the EFI Disk Label

Keep the following restrictions in mind when determining whether to use disks greater than 1 terabyte is appropriate for your environment:

• The SCSI driver, ssd, currently only supports up to 2 terabytes. If you need greater disk capacity than 2 terabytes, use a volume management product like Solaris Volume Manager to create a larger device.

• Layered software products intended for systems with EFI-labeled disks might be incapable of accessing a disk with an EFI disk label.

• A disk with an EFI disk label is not recognized on systems running previous Solaris releases.

• The EFI disk label is not supported on IDE disks.

• You cannot boot from a disk with an EFI disk label.

• You cannot use the Solaris Management Console's Disk Manager Tool to manage disks with EFI labels. Use the format utility or the Solaris Management Console's Enhanced Storage Tool to manage disks with EFI labels, after you use the format utility to partition the disk.

• The EFI specification prohibits overlapping slices. The whole disk is represented by cxtydz.

• Provides information about disk or partition sizes in sectors and blocks, but not in cylinders and heads.

• The following format options are either not supported or are not applicable on disks with EFI labels:

  • The save option is not supported because disks with EFI labels do not need an entry in the format.dat file.

  • The backup option is not applicable because the disk driver finds the primary label and writes it back to the disk.