Use the Disk Manager tool to work with disks.
Display information about a specific disk, create Solaris disk partitions, list partitions, copy the layout of one disk to another disk of the same type, change the disk's Label (descriptive name), create fdisk partitions on an x86 computer, and change the active fdisk partition.
Contained on this page is some background information about a disk and how it is used. For detailed information, see System Administration Guide, Vol I on docs.sun.com.
A disk is composed of a stack of platters, separated from each other and mounted on a spindle. In the spaces between the platters, read/write heads ride just over the platter surfaces, reading information from the disk, or writing information to it.
To improve disk in/out performance, a disk is formatted -- laid out in a way that groups information and reduces the amount of movement the heads require to read and write information. The layout on the disk is built up of units, from the smallest (the sector) to the largest (the partition).
The smallest unit on a platter is the sector (also called the block), which contains 512 bytes. A series of contiguous sectors makes up a track. The tracks on each platter are concentric, and each track can be read or written to as the disk rotates, without moving the read/write heads.
A cylinder consists of all the tracks that occupy the same position on all of the platters. Because a disk is constantly spinning, and because all the read/write heads move as a unit, the most efficient way for the heads to read and write to the disk is to have all the blocks containing related information located in a single cylinder.
Cylinders themselves are grouped by function. The groups of cylinders are called partitions (also called slices) and are the primary portions of the disk that are administered. On Sun systems, a disk can contain up to eight partitions, labeled 0 through 7. On x86 systems, a disk can contain up to 10 partitions, labeled 0-9. Each partition contains a single file system, and no file system can span multiple partitions.
Following are descriptions of the most commonly-used disk partitions. Included are the types of files typically included in each (although you can put any files you want in any partition):
boot - stores information used for booting the computer.
root - operating system files and directories (usually partition 0).
swap - disk space reserved for swapping program components in and
out of memory, when the programs are too large to fit entirely in
memory (partition 1 is often used).
usr - contains system commands (executables) to be run by users
(usually partition 6).
backup - refers to the whole disk (usually partition 2).
stand - used for standalone programs.
var - for keeping system files and directories likely to change in
size over the life of the local system, including system logs, editor
backup files, and so forth.
home - the location for files created by the user (usually
partition 7).
altsctr - (alternate sector) when a sector is not written
correctly, it is marked as bad and mapped to one in the altsctr partition.
cache - a local storage area for data stored on a server. After
remote files are referenced once, they can subsequently be retrieved
from the local cache.
On x86 computers, disks are divided into up to four fdisk partitions.
Each fdisk partition is reserved for a particular operating system,
Solaris, for example. Solaris places 10 partitions, numbered 0-9 on
the Solaris fdisk partition of the x86 system.