Solaris Default FileSystem Partition

Slice	File System	Description
0	root	Root (/) is the top of the hierarchical file tree. It holds files and directories that make up the operating system. The root directory contains the directories and files critical for system operation, such as the kernel, the device drivers, and the programs used to boot the system.The root (/) file system is always in slice 0.
1	swap	Provides virtual memory or swap space. Swap space is used when you’re running programs too large to fit in the computer’s memory. The Solaris operating environment then “swaps” programs from memory to the disk and back, as needed. Although it is not technically required, it is common for the swap slice to be located in slice 1 unless /var is set up as a file system. If  /var is set up,the interactive installation places /var on slice 1, and it places swap on slice 3.
2	Entire Disk	Refers to the entire disk and is defined automatically by Sun’s format utility and the Solaris installation programs. The size of this slice should not be Changed.
3	/var	This slice is unassigned by default. In Solaris 10, if you let the Sun installation program auto layout the slices, it will place the /var directory under slice 0 with the root file system. However, if during the installation, /var is selected to have its own slice, the installation program will place /var onto slice 1 and will move swap to slice 3. The /var file system is for files and directories likely to change or grow over the life of the local system. These include system logs, vi and ex backup files, printer and email spool files, backups of OS patches, and UUCP files. On a server, it’s a good idea to have these files in a separate file system so that they cannot fill up the root slice.
4		By default, slice 4 is unassigned and available for use.
5	/opt	This slice is unassigned by default. In Solaris 10, the /opt directory is put under slice 0 by default with the root file system. However, if during the installation, /opt is selected to have its own slice, the installation program will place /opt onto slice 5. /opt holds additional Sun software packages and optional third-party software that have been added to a system. If a slice is not allocated for this file system during installation, the /opt directory is put in slice 0, the root (/) file system.
6	/usr	This slice is unassigned by default. In Solaris 10, the /usr directory is put under slice 0 by default with the root file system. However, if during the installation, /usr is selected to have its own slice, the installation program will place /usr onto slice 6. / usr contains operating system commands also known as executable designed to be run by users.Files that can be used on all types of systems (such as man pages) are in /usr/share. If /usr is placed on slice 0, slice 6 becomes an unallocated slice.
7	/export/home	Holds files created by users. On a standard system, /home is a mount point that points to /export/home .