SPARC: Disk Slices
The following table describes the slices on a SPARC based system.
Table 32-2 SPARC: Customary Disk Slices
Slice | File System | Usually Found on Client or Server
Systems? | Comments |
|---|
0 | root (/) | Both | Holds files and directories that make up the operating
system. EFI - You cannot
boot from a disk with an EFI label. |
1 | swap | Both | Provides virtual
memory, or swap space. |
2 | -- | Both | VTOC - Refers to the entire disk, by convention.
The size of this slice should not be changed. EFI - Optional slice to be defined based on your site's needs. |
3 | /export | Both | Optional slice that can be defined based on your site's
needs. Can be used on a server to hold alternative versions of
operating systems that are required by client systems. |
4 | | Both | Optional slice to
be defined based on your site's needs. |
5 | | Both | Optional slice to
be defined based on your site's needs. Can be used to hold application
software added to a system. If a slice is not allocated for the /opt file system during installation, the /opt
directory is put in slice 0. |
6 | /usr | Both | Holds operating system commands (also known as executables).
This slice also holds documentation, system programs (init
and syslogd, for example) and library routines. |
7 | /home or /export/home | Both | VTOC - Holds files that are created by users. EFI - Not applicable. |
8 | N/A | N/A | VTOC - Not
applicable. EFI - A reserved
slice created by default. This area is similar to the VTOC's alternate cylinders.
Do not modify nor delete this slice. |
x86: Disk Slices
On x86 based systems, disks are divided into fdisk
partitions. An fdisk partition is a section of the disk
that reserved for a particular operating system, such as the Solaris release.
The Solaris release places ten slices, numbered 0-9, on a Solaris fdisk partition as shown in the following table.
Table 32-3 x86: Customary Disk Slices
Slice | File System | Usually Found on Client or Server Systems? | Purpose |
|---|
0 | root (/) | Both | Holds the files
and directories that make up the operating system. |
1 | swap | Both | Provides virtual
memory, or swap space. |
2 | -- | Both | Refers to the entire
disk, by convention. The size of this slice should not be changed. |
3 | /export | Both | Optional slice to be defined based on your site's needs. Can be
used on a server to hold alternative versions of operating systems that are
required by client systems. |
4 | | | Optional slice to be defined based
on your site's needs. |
5 | | Both | Optional slice to
be defined based on your site's needs. Can be used to hold application
software added to a system. If a slice is not allocated for the /opt file system during installation, the /opt
directory is put in slice 0. |
6 | /usr | Both | Holds operating system commands (also known as executables).
This slice also holds documentation, system programs (init
and syslogd, for example) and library routines. |
7 | /home or /export/home | Both | Holds files that are created by users. |
8 | -- | Both | Contains information
necessary for to boot the Solaris environment from the hard disk. The slice
resides at the beginning of the Solaris fdisk partition
(although the slice number itself does not indicate this fact), and is known
as the boot slice. |
9 | -- | Both | Provides an area
that is reserved for alternate disk blocks. Slice 9 is known as the alternate
sector slice. |
Using Raw Data Slices
The SunOS operating system stores the disk label in block 0 of each
disk. So, third-party database applications that create raw data slices must
not start at block 0, or 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 operating
system software 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 operating system software.
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:
Servers
Standalone systems
Each system configuration can use slices in a different way. The following
table lists some examples.
Table 32-4 System Configurations and Slices
Slice | Servers | Standalone Systems |
|---|
0 | root | root |
1 | swap | swap |
2 | -- | -- |
3 | /export | -- |
6 | /usr | /usr |
7 | /export/home | /home |
For more information about system configurations, see Overview of System Types.
Note - The Solaris installation program provides default slice sizes
based on the software you select for installation.
The 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 Solaris system.
The following table shows the features and associated benefits that
the format utility provides.
Table 32-5 Features and Benefits of the format Utility
Feature | Benefit |
|---|
Searches your system for all attached
disk drives | Reports on
the following: |
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 so individual
file systems can be created on separate slices |
Labels a disk | Writes disk name and configuration information
to the disk for future retrieval (usually for repair operations) |
The format utility options are fully described in Chapter 36, The format Utility (Reference).
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