Solaris 11 Directory Hierarchy

A complete description of the Solaris file system hierarchy is given below. The following table provides a brief overview of the most common directories. Its very much important to understand the Solaris Directory Hierarchy for basic level troubleshoot. After reading this you will get better understanding of Solaris filesystem structure.

/  - Root

• Primary hierarchy root and root directory of the entire file system hierarchy.
• Every single file and directory starts from the root directory.
• Only root user has write privilege under this directory.
• /  is also the root account home directory.

/bin 

• Binaries. Both root user and non-root user executable commands resides here. 
• It's symbolic link or soft link to /usr/bin. Hence the information under /bin and /usr/bin remains same.

/sbin

• Single user bin directory contains essential executable.
• It has the root user accessible commands. These commands are available when /usr/bin is NOT mounted. 
• It contains many system administrative commands and utilities.

/etc 

•  Holds the SYSTEM Configurations
• /etc/hosts - a file having the information about the hostnames and IP of the systems which are connected in the same network.
• /etc/issue    - The contents of the this file will be displayed to all before login to the system.
• /etc/default - The directory which holds the number of default parameters of the system
• /etc/cron.d  -  Config info for cron utility 
• /etc/inet      -  Config files - Network Services 
• /etc/init.d    -  Scripts to STOP & START services
• /etc/lp         -  Config info for printer 
• /etc/rc#.d    -  Scripts for various run levels  
• /etc/nfs       -  Config info for NFS server logging
• /etc/skel     -  Default shell initialization files
• /etc/motd    -  Message Of The Day contents of this file will be displayed for every user at the time of login.

/dev  

• provides logical information about the devices connected to the system
• /dev/dsk - Is a block device. A block device is a device with a file system.
• /dev/rdsk - Is a raw disk. A device without the file system.
• /dev/sound - sound driver inforamation
• /dev/term - provides information on the serial ports
• /dev/pts - provides information on the pseudo terminals
• /dev/swap - information on default swap device
• /dev/md - Solaris Volume Manager meta device information
• /dev/rmt - raw magnetic tapes
• /devices - provides information about the physical devices.

/usr 

•  Unix System Resources
• Contains programs, scripts and libraries that are used by all system users
• Contains Other link such as spool, news, man, mail.
• /usr/ccs - 'C' compling programs 
• /usr/include - Header files for 'C' programs 
• /usr/dt - CDE programs and files 
• /usr/java - java programs and its libraries 
• /usr/tmp - symbolic link to /var/tmp 
• /usr/opt - Configuration information for optional packages 
• /usr/sadm - system administration files and directories

/usr/bin 

• Standard system command
• binaries. Executable that can be executed by both root user and non-root user.

/proc 

•  Process directory. This directory stores current process related information. 
•  Every process has its own sub-directory in /proc.
• This is a pseudo filesystem contains information about running process. For example: /proc/{pid} directory contains information about the process with that particular PID

/var  

• Directory of varying files, includes temporary, logging, or status files
• /var/crash    - This directory will eventually hold system crash dumps
• /var/core     -  This directoy have the Core files when a process or application terminates abnormally.
• /var/mail     -  Contains user mailbox files
• /var/spool    - Holds spool files, for instance for mail, news, and printing (lpd) and other queued work
• /var/tmp      - Temp files needed across reboots.
• /var/lib         - Packages and database files 

/tmp

• A place for temporary files. Many systems clear this directory upon startup

/kernel 

• Core of the operating system. (genunix) will have the initial booting modules. 
• Contains kernel components common to all platforms within a particular instruction set that are needed for booting the system.

/platform

• Contains platform definition files.
• This is dependent on hardware and will be loaded followed by /kernel.

/lib 

• Contains library files that supports the binaries located under /bin and /sbin
• Library filenames are lib*.so.

/system/contract

• Used by SMF to track processes that compose a service. 
• A file system used for creating, controlling & observing contracts, which are relationships between processes & system resources. ( This directory can be seen in Sun Solaris 10)

/boot

• Contains all the important files which are required for successful booting process
• Will provide the information about the boot loaders

/opt

• Optional mount point for third-party software. 

/export/home

•  default location for creating a user's home directory it's shared directory.

/mnt    

•  This is the optional directory for temporarily mounts

/lost+found    

• will be empty and is created at the time of creating a file system.