vfstab

vfstab, short for Virtual File System Table, is a configuration file used by Solaris and related Unix systems to describe the file systems that should be mounted automatically at boot or on demand. It is read during system startup and can be used by the mount -a command to mount all listed file systems. The file is typically located at /etc/vfstab.

Each non-comment line in vfstab defines one filesystem and consists of six fields: special, dir, vfstype, mntopts, dump, and pass. The special field names the block device or remote filesystem (for example /dev/dsk/c1t0d0s0 or server:/export). The dir field is the mount point, such as / or /var. The vfstype field specifies the filesystem type (for example ufs, zfs, or nfs). The mntopts field contains mount options (such as rw, ro, or network-specific options). The dump field is used by the dump backup utility and typically holds 0 or 1. The pass field indicates the fsck pass number at boot time; 0 disables automatic checks, while 1 or 2 set the check order.

Entries can be marked with noauto in mntopts to prevent automatic mounting at boot, allowing manual mounting or mounting via automount. NFS and other network filesystems may be listed here to enable mounting on demand or at boot, depending on options and system configuration. ZFS datasets may also appear with vfstype set to zfs, depending on the system setup.

Editing vfstab requires caution, as incorrect entries can prevent the system from mounting essential filesystems during boot. After changes, administrators often test with mount -a or mount specific entries to verify correctness.