Manually mounting file systems every time you wanted to access them would be a very time-consuming and error-prone. To avoid these problems, the virtual file system table (the /etc/vfstab file) provides a list of file systems and information on how to mount them.
The /etc/vfstab file provides two important features:
You can specify file systems to automatically mount when the system boots. ZFS file systems are automatically mounted at boot time by an SMF service without entries in the vfstab file.
You can mount file systems by using only the mount point name. The /etc/vfstab file contains the mapping between the mount point and the actual device slice name.
A default /etc/vfstab file is created when you install a system, depending on the selections during installation. However, you can edit the /etc/vfstab file on a system whenever you want. To add an entry, the information you need to specify is as follows:
The device where the file system resides
The file system mount point
File system type
Whether you want the file system to mount automatically when the system boots (by using the mountall command)
Any mount options
The following is an example of an /etc/vfstab file for a system that runs a UFS root file system. Comment lines begin with #. This example shows an /etc/vfstab file for a system with two disks (c0t0d0 and c0t3d0).
$ more /etc/vfstab #device device mount FS fsck mount mount #to mount to fsck point type pass at boot options # fd - /dev/fd fd - no - /proc - /proc proc - no - /dev/dsk/c0t0d0s1 - - swap - no - /dev/dsk/c0t0d0s0 /dev/rdsk/c0t0d0s0 / ufs 1 no - /dev/dsk/c0t0d0s6 /dev/rdsk/c0t0d0s6 /usr ufs 1 no - /dev/dsk/c0t0d0s7 /dev/rdsk/c0t0d0s7 /export/home ufs 2 yes - /dev/dsk/c0t0d0s5 /dev/rdsk/c0t0d0s5 /opt ufs 2 yes - /devices - /devices devfs - no - sharefs - /etc/dfs/sharetabsharefs - no - ctfs - /system/contract ctfs - no - objfs - /system/object objfs - no - swap - /tmp tmpfs - yes -
In this example, root (/) and /usr, the mount at boot field value is specified as no. These file systems are mounted by the kernel as part of the boot sequence before the mountall command is run.
The following vfstab example if from a system that runs a ZFS root file system.
# cat /etc/vfstab #device device mount FS fsck mount mount #to mount to fsck point type pass at boot options # fd - /dev/fd fd - no - /proc - /proc proc - no - /dev/zvol/dsk/rpool/swap - - swap - no - /devices - /devices devfs - no - sharefs - /etc/dfs/sharetabsharefs - no - ctfs - /system/contract ctfs - no - objfs - /system/object objfs - no - swap - /tmp tmpfs - yes -
ZFS file systems are mounted automatically by the SMF service at boot time. You can mount ZFS file systems from the vfstab by using the legacy mount feature. For more information, see Oracle Solaris ZFS Administration Guide.
For descriptions of each /etc/vfstab field and information on how to edit and use the file, see Chapter 18, Mounting and Unmounting File Systems (Tasks).