System Administration Guide, Volume I

Commonly Used Mount Options

Table 28-3 describes the commonly used mount options that you can specify with the -o option of the mount command. If you specify multiple options, separate them with commas (no spaces). For example, -o ro,nosuid.

For a complete list of mount options for each file system type, refer to the specific mount command man pages (for example, mount_ufs(1M)).

Table 28-3 Commonly Used -o Mount Options


Option	File System	Description
`bg \| fg`	NFS	If the first attempt fails, retries in the background (`bg`) or in the foreground (`fg`). The default is `fg`.
`f`	UFS	Fakes an entry in `/etc/mnttab`, but doesn't really mount any file systems.
`hard \| soft`	NFS	Specifies the procedure if the server does not respond. `soft` indicates that an error is returned. `hard` indicates that the retry request is continued until the server responds. The default is `hard`.
`intr \| nointr`	NFS	Specifies whether keyboard interrupts are allowed to kill a process hung while waiting for a response on hard-mounted file systems. The default is `intr` (interrupts allowed).
`largefiles \| nolargefiles`	UFS	Enables you to create file systems containing files larger than 2 Gbytes. The `largefiles` option means that a filesystem mounted with this option may contain files larger than 2 Gbytes, but it is not a requirement. The default is `largefiles`.
`logging \| nologging`	UFS	Enables logging for the file system. UFS logging is the process of storing transactions (changes that make up a complete UFS operation) into a log before the transactions are applied to the UFS file system. Because the file system can never become inconsistent, `fsck` can be bypassed, which reduces the time to reboot a system if it crashes, or after an unclean halt. The log is allocated from free blocks on the file system, and is sized approximately 1 Mbyte per 1 Gbyte of file system, up to a maximum of 64 Mbytes. The default is `nologging`.
`m`	CacheFS, NFS, PCFS, S5FS, UFS	Mounts the file system without making an entry in `/etc/mnttab`.
`noatime`	UFS	Ignores access time updates on files, except when they coincide with updates to the `ctime` or `mtime`. See stat(2). This option reduces disk activity on file systems where access times are unimportant (for example, a Usenet news spool). The default is normal access time (`atime`) recording.
`remount`	NFS, S5FS, UFS	Remounts a read-only file system as read-write (using the `rw` option). This option can be used only in conjunction with the `f`, `logging \| nologging`, and `m` options. This option works only on currently mounted read-only file systems.
`retry=n`	NFS	Retries the mount operation when it fails. `n` is the number of times to retry.
`ro \| rw`	CacheFS, NFS, PCFS, UFS, S5FS	Specifies read/write or read-only. If you do not specify this option, the default is read/write.
`suid \| nosuid`	CacheFS, HSFS, NFS, S5FS, UFS	Allows or disallows `setuid` execution The default is to allow `setuid` execution.