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Oracle Solaris Administration: Devices and File Systems     Oracle Solaris 11 Information Library
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Document Information

About This Book

1.  Managing Removable Media (Overview)

2.  Managing Removable Media (Tasks)

3.  Accessing Removable Media (Tasks)

4.  Writing CDs and DVDs (Tasks)

5.  Managing Devices (Overview/Tasks)

6.  Dynamically Configuring Devices (Tasks)

7.  Using USB Devices (Overview)

8.  Using USB Devices (Tasks)

9.  Using InfiniBand Devices (Overview/Tasks)

10.  Managing Disks (Overview)

What's New in Disk Management?

Identifying Devices by Physical Locations

Multiple Disk Sector Size Support

Two-Terabyte Disk Support for Installing and Booting the Oracle Solaris OS

iSNS Support in the Solaris iSCSI Target and Initiator

Solaris COMSTAR iSCSI Support

x86: Disk Management in the GRUB Boot Environment

Support for SCSI Disks That are Larger Than 2 Terabytes

Where to Find Disk Management Tasks

Overview of Disk Management

Disk Terminology

About Disk Labels

EFI Disk Label

Comparison of the EFI Label and the VTOC Label

Restrictions of the EFI Disk Label

Support for EFI-Labeled Disks on x86 Systems

Installing a System With an EFI-Labeled Disk

Managing Disks With EFI Disks Labels

Troubleshooting Problems With EFI Disk Labels

About Disk Slices

Disk Slices

Using Raw Data Slices

format Utility

When to Use the format Utility

Guidelines for Using the format Utility

Formatting a Disk

Partitioning a Disk

Partition Table Terminology

Displaying Partition Table Information

Using the Free Hog Slice

11.  Administering Disks (Tasks)

12.  SPARC: Setting Up Disks (Tasks)

13.  x86: Setting Up Disks (Tasks)

14.  Configuring Storage Devices With COMSTAR

15.  Configuring and Managing the Oracle Solaris Internet Storage Name Service (iSNS)

16.  The format Utility (Reference)

17.  Managing File Systems (Overview)

18.  Creating and Mounting File Systems (Tasks)

19.  Configuring Additional Swap Space (Tasks)

20.  Copying Files and File Systems (Tasks)

21.  Managing Tape Drives (Tasks)


Overview of Disk Management

Managing disks in the Oracle Solaris OS usually involves setting up the system and running the Oracle Solaris installation program to create the appropriate disk slices and file systems and to install the Oracle Solaris OS. Occasionally, you might need to use the format utility to add a new disk drive or replace a defective disk drive.

Disk Terminology

Before you can effectively use the information in this section, you should be familiar with basic disk architecture. In particular, you should be familiar with the following terms:

Disk Term
A concentric ring on a disk that passes under a single stationary disk head as the disk rotates.
The set of tracks with the same nominal distance from the axis about which the disk rotates.
Section of each disk platter. A sector holds 512 bytes.
A data storage area on a disk. A disk block is 512 bytes.
Disk controller
A chip and its associated circuitry that controls the disk drive.
Disk label
The first sector of a disk that contains disk geometry and partition information.
Device driver
A kernel module that controls a hardware or virtual device.

For additional information, see the product information from your disk's manufacturer.

About Disk Labels

A special area of every disk is set aside for storing information about the disk's controller, geometry, and slices. This information is called the disk's label. Another term that is used to described the disk label is the VTOC (Volume Table of Contents) on a disk with a VTOC label. To label a disk means to write slice information onto the disk. You usually label a disk after you change its slices.

The Oracle Solaris release supports the following two disk labels:

If you fail to label a disk after you create slices, the slices will be unavailable because the OS has no way of “knowing” about the slices.

EFI Disk Label

The EFI label provides support for physical disks and virtual disk volumes that are greater than 2 TB in size. This release also includes updated disk utilities for managing disks greater than 2 TB in size.

The following file system products support file systems greater than 1 TB in size:

The VTOC label is still available for disks less than 2 terabytes in size. If you are only using disks smaller than 2 TB 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 2 TB in size or less with an EFI label. For more information, see Example 11-5.

You can use the format -e command to apply an EFI label to a disk if the system is running the appropriate Oracle Solaris release. However, you should review the important information in Restrictions of the EFI Disk Label before attempting to apply an EFI label.

You can also use the format -e command to reapply a VTOC label if the EFI label is no longer needed. For example:

# format -e
Specify disk (enter its number): 2
selecting c0t5d0
[disk formatted]
format> label
[0] SMI Label
[1] EFI Label
Specify Label type[1]: 0
Warning: This disk has an EFI label. Changing to SMI label will erase all
current partitions.
Continue? yes
Auto configuration via format.dat[no]? 
Auto configuration via generic SCSI-2[no]? 
format> quit


Caution - Keep in mind that changing disk labels will destroy any data on the disk.

Comparison of the EFI Label and the VTOC Label

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

Restrictions of the EFI Disk Label

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

Support for EFI-Labeled Disks on x86 Systems

Oracle Solaris support for the EFI disk label is available on x86 systems. Use the following command to add an EFI label on an x86 system:

# format -e
> [0] SMI Label
> [1] EFI Label
> Specify Label type[0]: 1
> WARNING: converting this device to EFI labels will erase all current
> fdisk partition information. Continue? yes

Previous label information is not converted to the EFI disk label.

You will have to recreate the label's partition information manually with the format command. You cannot use the fdisk command on a disk with an EFI label that is 2 terabytes in size. If the fdisk command is run on disk that is greater than 2 TB in size to create a Solaris partition, the Solaris partition is limited to 2 TB. For more information about EFI disk labels, see the preceding section.

Installing a System With an EFI-Labeled Disk

An Oracle Solaris root pool disk must have an SMI label. The Oracle Solaris 11 installation utilities automatically relabel any disk that is selected as a root pool disk with an SMI label.

Managing Disks With EFI Disks Labels

Use the following table to locate information on managing disks with EFI disk labels.

For More Information
If the system is already installed, connect the disk to the system.
Create a ZFS file system.

Troubleshooting Problems With EFI Disk Labels

Use the following error messages and solutions to troubleshoot problems with EFI-labeled disks.


Boot a system running SPARC or x86 kernel with a disk greater than 1 terabyte.

Error Message
Dec  3 09:12:17 holoship scsi: WARNING: /sbus@a,0/SUNW,socal@d,10000/
sf@1,0/ssd@w50020f23000002a4,0 (ssd1):
Dec  3 09:12:17 holoship corrupt label - wrong magic number

You attempted to add a disk to a system running an older Solaris release.


Add the disk to a system running the Solaris release that supports the EFI disk label.

About Disk Slices

Files stored on a disk are contained in file systems. Each file system on a disk is assigned to a slice, which is a group of sectors set aside for use by that file system. Each disk slice appears to the Oracle Solaris OS (and to the system administrator) as though it were a separate disk drive.

For information about file systems, see Chapter 17, Managing File Systems (Overview).

Note - Slices are sometimes referred to as partitions. Certain interfaces, such as the format utility, refer to slices as partitions.

When setting up slices, remember these rules:

Slices are set up slightly differently on SPARC and x86 platforms. The following table summarizes the differences.

Table 10-1 Slice Differences on SPARC and x86 Platforms

SPARC Platform
x86 Platform
The entire disk is devoted to Oracle Solaris OS.
Disk is divided into fdisk partitions, one fdisk partition per operating system.
VTOC – The disk is divided into 8 slices, numbered 0-7.

EFI – The disk is divided into 7 slices, numbered 0-6.

VTOC – The Solaris fdisk partition is divided into 10 slices, numbered 0–9.

EFI – The disk is divided into 7 slices, numbered 0-6

Disk Slices

On a system with ZFS file systems, disk slices are only required for the ZFS root pool that contains the ZFS root file system. In general, the ZFS root pool is contained in slice 0. The ZFS root pool must exist on a slice or mirrored slices because of a long-standing boot limitation. For non-root storage pools, you can use whole disks. ZFS file systems do not correspond to specific disk slices. Managing whole disks is easier than managing disks with slices.

On x86 systems:

Note - On a disk with a VTOC label, do not modify slice or use slice 2 to store a file system. The installgrub command does not work correctly if slice 2 is modified in any way.

Using Raw Data Slices

The disk label is stored in block 0 of each disk. So, third-party database applications that create raw data slices must not start at block 0. Otherwise, the disk label will be overwritten, and the data on the disk will be inaccessible.

Do not use the following areas of the disk for raw data slices, which are sometimes created by third-party database applications:

format Utility

Read the following overview of the format utility and its uses before proceeding to the “how-to” or reference sections.

The format utility is a system administration tool that is used to prepare hard disk drives for use on your Oracle Solaris system.

The following table shows the features and associated benefits that the format utility provides.

Table 10-2 Features and Benefits of the format Utility

Searches your system for all attached disk drives
Reports on the following:
  • Target location

  • Disk geometry

  • Whether the disk is formatted

  • If the disk has mounted partitions

Retrieves disk labels
Convenient for repair operations
Repairs defective sectors
Allows administrators to repair disk drives with recoverable errors instead of sending the drive back to the manufacturer
Formats and analyzes a disk
Creates sectors on the disk and verifies each sector
Partitions a disk
Divides a disk into slices. ZFS file systems do not correspond to disk slices except for the ZFS root pool.
Labels a disk
Writes disk name and configuration information to the disk for future retrieval (usually for repair operations)

The format utility options are described in Chapter 16, The format Utility (Reference).

When to Use the format Utility

Disk drives are partitioned and labeled by the Oracle Solaris installation utility when you install the Oracle Solaris release. You can use the format utility to do the following:

The main reason a system administrator uses the format utility is to partition a disk. These steps are covered in Chapter 12, SPARC: Setting Up Disks (Tasks) and Chapter 13, x86: Setting Up Disks (Tasks).

See the following section for guidelines on using the format utility.

Guidelines for Using the format Utility

Table 10-3 format Utility Guidelines

For More Information
Format a disk.
  • Any existing data is destroyed when you reformat a disk.
  • The need for formatting a disk drive has decreased as more and more manufacturers ship their disk drives formatted and partitioned. You might not need to use the format utility when you add or replace a disk drive to an existing system.

  • If a disk has been relocated and is displaying many disk errors, you can attempt to relabel it.

Set up a disk that contains a ZFS root file system.
In a non-redundant configuration, a ZFS root file system data from the damaged disk must be restored from a backup medium. Otherwise, the system will have to be reinstalled by using the installation utility.
Create a disk slice for a root pool.
  • The best way to use a ZFS storage pool is by creating a pool with whole disks.
  • If a disk is intended to be used for a root pool, you must create a disk slice. This is long-standing boot limitation.

Set up a disk that contains a ZFS file system.
A disk that is used for a non-root ZFS file system usually contains space for user or data files. You can attach or add a another disk to a root pool or a non-root pool for more disk space.

Formatting a Disk

In most cases, disks are formatted by the manufacturer or reseller. So, they do not need to be reformatted when you install the drive. To determine if a disk is formatted, use the format utility. For more information, see How to Determine if a Disk Is Formatted.

If you determine that a disk is not formatted, use the format utility to format the disk.

When you format a disk, you accomplish two steps:


Caution - Formatting a disk is a destructive process because it overwrites data on the disk. For this reason, disks are usually formatted only by the manufacturer or reseller. If you think disk defects are the cause of recurring problems, you can use the format utility to do a surface analysis. However, be careful to use only the commands that do not destroy data. For details, see How to Format a Disk.

A small percentage of total disk space that is available for data is used to store defect and formatting information. This percentage varies according to disk geometry, and decreases as the disk ages and develops more defects.

Formatting a disk might take anywhere from a few minutes to several hours, depending on the type and size of the disk.