System Administration Guide, Volume 1

The Default Solaris File Systems

The Solaris file system is hierarchical, starting with the root directory (/) and continuing downwards through a number of directories. The Solaris installation process enables you to install a default set of directories and uses a set of conventions to group similar types of files together. The table below provides a summary of the default Solaris file systems, and shows the type of each file system.

The root (/) and /usr file systems are both needed to run a system. Some of the most basic commands from the /usr file system (like mount) are included in the root (/) file system so that they are available when the system boots or is in single-user mode and /usr is not mounted. See Chapter 40, UFS File System Reference for more detailed information on the default directories for the root (/) and /usr file systems.

Table 34-2 The Default Solaris File Systems


File System or Directory	File System Type	Description
root (`/`)	UFS	The top of the hierarchical file tree. 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. It also contains the mount point directories where local and remote file systems can be attached to the file tree.
`/usr`	UFS	System files and directories that can be shared with other users. Files that run only on certain types of systems are in the `/usr` directory (for example, SPARC executables). Files (such as man pages) that can be used on all types of systems are in `/usr/share`.
`/export/home` or `/home`	NFS, UFS	The mount point for users' home directories, which store users work files. By default `/home` is an automounted file system. On standalone systems, `/home` might be a UFS file system on a local disk slice.
`/var`	UFS	System files and directories that are likely to change or grow over the life of the local system. These include system logs, `vi` and `ex` backup files, and `uucp` files.
`/opt`	NFS, UFS	Mount point for optional, third-party software. On some systems, `/opt` might be a UFS file system on a local disk slice.
`/tmp`	TMPFS	Temporary files, cleared each time the system is booted or the `/tmp` file system is unmounted.
`/proc`	PROCFS	A list of active processes, by number.