Overview of Disk Management
Managing disks in the Solaris OS usually involves setting up the system and running the Solaris installation program to create the appropriate disk slices and file systems and to install the Solaris OS. Occasionally, you might need to use the format utility to add a new disk drive or replace a defective disk drive.
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:
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 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. 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 64-bit: 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 Sun QFS, Sun SAM-FS, and Sun SAM-QFS File System Administrator’s Guide.
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 11-6.
You can use the format -e command to apply an EFI label to a disk if the system is running the appropriate Solaris release. However, you should review the important information in Restrictions of the EFI Disk Label before attempting to apply an EFI label.
Comparison of the EFI Label and the VTOC Label
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
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 >  SMI Label >  EFI Label > Specify Label type: 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 greater than 1 terabyte in size. The fdisk command is not intended for disks that are larger than 1 terabyte. For more information about EFI disk labels, see the preceding section.
Installing a System With an EFI-Labeled Disk
The Solaris installation utilities automatically recognize disks with EFI labels. However, you cannot use the Solaris installation program to repartition these disks. You must use the format utility to repartition an EFI-labeled disk before or after installation. The Solaris Upgrade and Live Upgrade utilities also recognize a disk with an EFI label. However, you cannot boot a system from an EFI-labeled disk.
After the Solaris release is installed on a system with an EFI-labeled disk, the partition table appears similar to the following:
Current partition table (original): Total disk sectors available: 2576924638 + 16384 (reserved sectors) Part Tag Flag First Sector Size Last Sector 0 root wm 34 1.20TB 2576924636 1 unassigned wm 0 0 0 2 unassigned wm 0 0 0 3 unassigned wm 0 0 0 4 unassigned wm 0 0 0 5 unassigned wm 0 0 0 6 unassigned wm 0 0 0 8 reserved wm 2576924638 8.00MB 2576941021
Managing Disks With EFI Disks Labels
Use the following table to locate information on managing disks with EFI disk labels.
*If a ZFS file system or UFS file system does not meet your needs, consider a QFS file system.
Troubleshooting Problems With EFI Disk Labels
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 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
Solaris Volume Manager, previously the Solstice DiskSuiteTM, has a partitioning feature, soft partitions. Soft partitions enable more than eight partitions per disk.
For general information about Solaris Volume Manager, see Chapter 2, Storage Management Concepts, in Solaris Volume Manager Administration Guide. For information on soft partitions, see Chapter 12, Soft Partitions (Overview), in Solaris Volume Manager Administration Guide.
The following table describes the slices that might be found on a system that runs the Solaris OS.
On x86 systems:
Table 10-2 Customary Disk Slices
Note - On a disk with a VTOC label, do not modify slice or use slice 2 to store a file system. Products, such as Solaris Volume Manager and Live Upgrade, do 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:
Slice Arrangements on Multiple Disks
Although a single large disk can hold all slices and their corresponding file systems, two or more disks are often used to hold a system's slices and file systems.
Note - A slice cannot be split between two or more disks. However, multiple swap slices on separate disks are allowed.
For instance, a single disk might hold the root (/) file system, a swap area, and the /usr file system, while another disk holds the /export/home file system and other file systems that contain user data.
In a multiple disk arrangement, the disk that contains the OS and swap space (that is, the disk that holds the root (/) and /usr file systems and the slice for swap space) is called the system disk. Other disks are called secondary disks or non-system disks.
When you arrange a system's file systems on multiple disks, you can modify file systems and slices on the secondary disks without having to shut down the system or reload the OS.
When you have more than one disk, you also increase input-output (I/O) volume. By distributing disk load across multiple disks, you can avoid I/O bottlenecks.
Determining Which Slices to Use
When you set up a disk's file systems, you choose not only the size of each slice, but also which slices to use. Your decisions about these matters depend on the configuration of the system to which the disk is attached and the software you want to install on the disk.
System configurations that need disk space are as follows:
Table 10-3 System Configurations and Slices
For more information about system configurations, see Overview of System Types in System Administration Guide: Basic Administration.
Note - The Solaris installation utility provides default slice sizes based on the software you select for installation.
The format utility is a system administration tool that is used to prepare hard disk drives for use on your Solaris system.
Table 10-4 Features and Benefits of the format Utility
The format utility options are described in Chapter 16, The format Utility (Reference).
When to Use the format Utility
See the following section for guidelines on using the format utility.
Guidelines for Using the format Utility
Table 10-5 format Utility Guidelines
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.