mount_ufs(8) on Solnix vs Linux and the BSDs
On Solnix, mount_ufs(8) is the illumos page for the ufs-specific part of mount, run as `mount -F ufs`, not as a standalone command. The only counterpart in the bundle is NetBSD, where mount_ffs [-o options] special node is the real command and mount_ufs is a backward-compatibility name.
The manual pages
- Solnix: mount_ufs(8) from
pkgs.solnix.illumos-world-man· illumos.org - NetBSD: mount_ufs(8) 11.0
What Solnix runs
A default Solnix system runs the illumos implementation. The header says it is not in /usr/bin, /usr/sbin or /sbin, so use `mount -F ufs ...` rather than calling mount_ufs by name. No other illumos variants are shipped. The bundle has no Linux, FreeBSD or OpenBSD counterpart page, so nothing is compared against those systems.
Differences
| Compared with | Topic | What differs |
|---|---|---|
| NetBSD | how the command is invoked | Solnix runs `mount -F ufs [generic_options] [-o specific_options] [-O] special | mount_point`. NetBSD runs `mount_ffs [-o options] special node`, and the page says mount(8) normally executes it at boot time.Source: Solnix mount_ufs(8) SYNOPSIS; NetBSD mount_ufs(8) SYNOPSIS, DESCRIPTION |
| NetBSD | file system type name | The Solnix page uses type ufs (`-F ufs`). NetBSD says the mount_ufs form is for backward compatibility only, and that fstab(5) entries should use type ffs, not ufs.Source: Solnix mount_ufs(8) SYNOPSIS; NetBSD mount_ufs(8) DESCRIPTION |
| NetBSD | where the options are documented | The Solnix page lists the ufs-specific -o options itself: logging, onerror, noatime, forcedirectio, quota, remount, xattr and others. NetBSD's page lists none and sends you to mount(8) for options and meanings.Source: Solnix mount_ufs(8) OPTIONS (-o specific_options); NetBSD mount_ufs(8) OPTIONS (-o) |
| NetBSD | overlay mount (-O) | Solnix accepts -O, described as an overlay mount. The NetBSD synopsis has only -o, so the bundle shows no -O there.Source: Solnix mount_ufs(8) SYNOPSIS, OPTIONS (-O); NetBSD mount_ufs(8) SYNOPSIS |
| NetBSD | default options and logging | On Solnix, with special and mount_point but no specific options, the default is rw. UFS logging is the default for all UFS file systems, and `nologging` turns it off. The NetBSD page states no defaults. Source: Solnix mount_ufs(8) DESCRIPTION, OPTIONS (logging | nologging); NetBSD mount_ufs(8) OPTIONS |
| NetBSD | filling in missing arguments | On Solnix, if only special or only mount_point is given, mount reads /etc/vfstab for the missing arguments and options. The NetBSD page requires both special and node and mentions fstab(5) only for the type name.Source: Solnix mount_ufs(8) DESCRIPTION (/etc/vfstab); NetBSD mount_ufs(8) SYNOPSIS, DESCRIPTION |
| NetBSD | mounting a file and the mnttab entry | Solnix can mount a file that contains a ufs file system as well as a block device (see lofiadm(8)). Its `m` option skips the /etc/mnttab entry. The NetBSD page documents neither.Source: Solnix mount_ufs(8) DESCRIPTION, OPTIONS (m); NetBSD mount_ufs(8) DESCRIPTION |
| NetBSD | path handling | NetBSD converts special and node to absolute paths before use. The Solnix page says a mount point that is a symbolic link is resolved, and the file system mounts on the directory it refers to. It does not mention absolute-path conversion. Source: NetBSD mount_ufs(8) DESCRIPTION; Solnix mount_ufs(8) DESCRIPTION |
| NetBSD | error handling and invalid options | Solnix `onerror=panic|lock|umount` sets the response to internal inconsistency, with panic as the default. Invalid ufs options give a warning and are ignored. NetBSD's BUGS says only that a corrupted file system can cause a crash. Source: Solnix mount_ufs(8) OPTIONS (-o, onerror); NetBSD mount_ufs(8) BUGS |
Standards
- POSIX: mount_ufs is not a POSIX.1-2024 utility.
- Solnix: The part of the Solnix page in the bundle has no STANDARDS or INTERFACE STABILITY section. It only notes that the POSIX standard requires access times to be marked on files, and that noatime ignores them unless the file is also modified.
- NetBSD: The NetBSD page has no STANDARDS section. HISTORY says a mount_ffs command appeared in NetBSD 1.1.
Writing portable scripts
- Do not call mount_ufs directly in scripts. Use mount(8) and keep a per-OS table for the file system type name (ufs on Solnix, ffs for NetBSD fstab entries).
- Treat the
-ooption names as system-specific. Check the Solnix mount_ufs(8) list and the NetBSD mount(8) page before reusing an option string.
Every difference here is taken from the manual pages linked above: Solnix's published page, Linux (man-pages and the GNU and util-linux manuals), FreeBSD, OpenBSD and NetBSD. Each row names its source. Where a manual is silent, this page is too. Compiled 2026-10-26. Found a mistake? Mail hackers@lists.solnix.io.