mount, umount - Mounts and unmounts file systems
/usr/sbin/mount [-d] [-r | -u | -w] [-o argument,...] [-t [no]type]
/usr/sbin/mount [-el] [-t [no]type]
/usr/sbin/mount -a [-fv] [-t [no]type]
/usr/sbin/mount [-d] [-r | -u | -w] [-o argument,...] [-t [no]type]
file-system | directory
/usr/sbin/umount -a | -A-b [-fv] [-t type] [-h host]
/usr/sbin/umount [-fv] file-system... | directory...
There are options for the mount and umount commands.
Options for mount:
Attempts to mount all the file systems described in the /etc/fstab
file. In this case, file-system and directory are taken from the
/etc/fstab file. If -t type is specified, all of the file systems in
the /etc/fstab file with that type will be mounted. Alternatively, if
type is prefixed with no, all the file systems in the /etc/fstab file
that do not have that type will be mounted. File systems are not nec‐
essarily mounted in the order listed in the /etc/fstab file. Mounts a
UNIX file system (UFS) even if it has not been unmounted cleanly or
checked by fsck for consistency. Also used to mount a CD-ROM UFS file
Do not employ the -d option to mount an AdvFS fileset. When an
AdvFS fileset is mounted with the -d option, AdvFS initializes
the domain transaction log. As a result, no domain recovery will
occur for previously incomplete operations (which could cause
data corruption). If you cannot mount a fileset, use the verify
command. Lists all mount points. Without this option, mount
does not list mount points served by either Automount or AutoFS.
Performs a fake mount and actually does not mount the file sys‐
tem. This option is used to verify the arguments you plan to use
with the mount command. Displays the value of all the file sys‐
tem options. Specifies a list of comma-separated arguments.
Every argument specified is used. Some arguments are valid for
all file system types, while others apply only to a specific
type. See the Options for mount -o Arguments section that is
specific to your file system type for a description of the argu‐
ments supported by that file system. Queries the device to
determine which file system or file systems are found on DVD or
CD media, and thus, how that device can be mounted. Mounts the
specified file system with read-only access. This option is the
equivalent of the following command: mount -o ro file-system
Physically write-protected and magnetic tape file systems must
be mounted with read-only access or errors will occur when
access times are updated, whether or not any explicit write is
attempted. Note that -r and -w are paired; the default is -w.
Specifies the file system type. The supported file systems are
advfs - Advanced File System (AdvFS)
ufs - UNIX File System (UFS)
nfs - Network File System (NFS)
mfs - Memory file system (RAM Disk) See mfs(8)
cdfs - ISO 9660 CD-ROM (Compact Disc Read Only Memory) File Sys‐
tem. See cdfs(4).
dvdfs - DVD-ROM (Digital Versatile Disk, Read-only) File System.
See dvdfs(4). This option mounts DVD-ROM disks formatted in the
Universal Disk Format (UDF).
dfs - DCE Distributed File System
efs - DCE Episode File System
fdfs - File Descriptor File System (used by streams)
ffm - File on File Mounting File System (used by streams)
procfs - Process File System (used by debuggers)
pcfs - PC File System
sysv - System V File System
See fstab(4) for a description of the valid file system types.
If the no prefix is used, all file types except the one speci‐
fied are mounted. Requests that the system remount a file sys‐
tem so that it can update any incore data blocks for UFS and
AdvFS type file systems.
If you mount a UFS file system in a cluster for read-only
access, you cannot use the -u option to update the file system
to read-write access. A UFS file system mounted for read-only
access is accessible by all cluster members; a UFS file system
mounted for read-write access is accessible only by the cluster
member on which the mount request is issued.
For CDFS, this option is used to change the attributes of a
mount, such as the version attribute. For example, CDFS is
mounted noversion by default. The following use of the -u option
shows how you can change the default: # mount -u-o version
/cdmntpnt Displays a message indicating which file system is
being mounted (verbose). Mounts the specified file system with
read/write access. This option is equivalent to the -o rw
option. Read/write is the default access.
Options for umount:
Attempts to unmount all the file systems currently mounted. Attempts
to unmount all the file systems listed in the /etc/fstab file. Broad‐
casts a message to all server machines in the subnetwork to remove the
client host's name from their NFS mountdtab files. Performs a fast
unmount operation that causes remote file systems to be unmounted with‐
out notifying the server. Unmounts all file systems listed in the
/etc/fstab file that are remotely mounted from host. Unmounts all file
systems listed in the /etc/fstab file that are of the specified type.
The -a option must be used together with the -t option. Displays a
message indicating the file system is being unmounted (verbose).
Options for mount -o Arguments
There are many arguments for the -o option; they are discussed in the
TruCluster mount - o Arguments
The following arguments are valid for TruCluster systems: Enables you
to specify the cluster member, identified by cluster_member_name, that
serves a given file system at startup.
This mount command option determines where the file system is
first mounted; it does not limit or determine the cluster mem‐
bers to which the file system might later be relocated or fail
The -o server=cluster_member_name option is valid only in a
cluster, and only for the AdvFS, UFS, MFS, NFS, CDFS, and DVDFS
file systems. MFS file systems support this option in a limited
fashion: the file system is mounted only if the specified server
is the local node.
For information on using this option, refer to the Distributing
File Systems Via the mount -o Command section of the Cluster
Administration manual. Enables cluster file system partition‐
ing. Use this option only in a cluster. For example: # mount -o
If a file system is already mounted, you cannot use this option
to update the mount status to server_only. You must first
unmount the file system and then remount it with the server_only
When you mount a UFS file system in a cluster for read/write
access, or when you mount an MFS file system in a cluster for
read-only or read/write access, the server_only option is used
These file systems are treated as partitioned file systems. That
is, the file system is accessible for both read-only and
read/write access only by the member that mounts it. Other clus‐
ter members cannot read from, or write to, the MFS or UFS file
system. There is no remote access; there is no failover.
If you want to mount a UFS file system for read-only access by
all cluster members, you must explicitly mount it read-only.
For information on using this option, refer to the Partitioning
File Systems section of the Cluster Administration manual.
AdvFS mount - o Arguments
The following arguments are valid for the Advanced File System (AdvFS):
Causes all files in the mounted fileset to use atomic-write data log‐
ging for the duration of the mount. Unlike chfile, which activates
data logging on a file in a manner that persists across mounts and
unmounts, the data logging provided by the -o adl mount option is tem‐
porary and lasts only for the duration of the mount. Additionally,
files using temporary -o adl data logging may be mmaped(), unlike files
that have had persistent data logging activated on them. The temporary
data logging is suspended until the last thread using the mmapped file
unmaps it. Finally, the use of chfile on a file that is using temporary
data logging causes the chfile command to override the temporary data
logging provided by the new mount and the file's I/O mode is changed
persistently according to the arguments given to the chfile command.
For more information see chfile(8). Enables an AdvFS fileset to be
mounted as a domain volume even though it has the same AdvFS domain ID
as a fileset that is already mounted.
AdvFS and UFS mount - o Arguments
The following arguments are valid for the AdvFS and UFS file systems:
Flushes to disk file access time changes for reads of regular files.
(Default behavior when neither atimes or noatimes is specified.) Marks
file access time changes made for reads of regular files in memory, but
does not flush them to disk until other file modifications occur. This
behavior does not comply with industry standards and is used to reduce
disk writes for applications with no dependencies on file access times.
Allows the file system to make use of expanded space on the underlying
storage device. The -o option can be used on the initial mount of a
file system or by way of the -u update option if the file system is
already mounted. For UFS, if you do not want to mount the file system,
or if you want to take only part of the available storage space, you
can use the extendfs command. See the extendfs(8) reference page for
There are several steps needed in order to expand a file system:
Make additional storage space available on the underlying stor‐
age device (that is, a LSM volume or hardware RAID LUN). For
non-LSM volumes, modify the disk label to include additional
storage. See the disklabel reference page for more information.
Use the mount command with the extend option to allow the file
system to use the additional storage.
For an unmounted AdvFS fileset, the following is an example of
# mount -o extend domain#fileset /ausr1
For a mounted AdvFS fileset, the following is an example of vol‐
# mount -u -o extend domain#fileset /ausr2
For an an unmounted UFS file system, the following is an example
of volume expansion:
# mount -o extend /dev/disk/dsk0g /useref
For a mounted UFS file system, the following is an example of
# mount -u -o extend /dev/disk/dsk0h /useracct
Refer to the System Administration manual for more information.
Allows read/write access. Allows read-only access. Allows
read/write access. Allows file system to be used as swap space.
Allows a file system to be mounted even if it was not cleanly
unmounted. Allows access to block and character-special
devices. Disallows access from the file system to either block
or character-special devices. Allows set-user-ID execution.
Prohibits set-user-ID execution. Causes all writes to be writ‐
ten immediately to disk as well as to the buffer cache. Speci‐
fies that writes may return before data is written to disk.
Enables the alternate smooth sync policy, in which modified
pages are not written to disk until they have been dirty and
idle for the smoothsync_age time period.
By default, modified pages are flushed after they have been
dirty for the smoothsync_age time period, regardless of contin‐
ued modifications to the page. Pages that have been mapped into
virtual memory will always use this default policy, regardless
of the smsync2 setting. The default smoothsync_age period is 30
seconds, and can be modified by editing the inittab file.
If you enable the smsync2 option on a mount point in an AdvFS
domain, the alternate smooth sync policy goes into effect for
all of the filesets in the domain. Allows binary execution.
Prohibits binary execution. Enables new files to inherit the
parent directory's group ID. This is the default and matches
BSD semantics. Applies SVID 3 semantics. For example, if the
parent directory's mode bits include IS_GID, then the new file
will inherit the parent's group ID. If IS_GID is off, then it
inherits the process group ID.
UFS mount - o Arguments
The following mount -o arguments are valid only for the UFS file sys‐
tem. Delays synchronously flushing metadata updates to disk.
Instead, metadata (such as inode, directory, and indirect blocks) is
flushed by the sync daemon. This mount option improves performance in
the following ways: Multiple updates to a block are accomplished with a
single write instead of with multiple writes of the same block, which
can occur during synchronous metadata updates. System responsiveness
improves when running metadata intensive applications. Metadata writes
to disk do not occur immediately.
Data might be lost if you use this option and your system
crashes before the sync daemon flushes the metadata to disk. Do
not use this option for the root (/) or /usr file systems.
You can use this option for a temporary file system, such as
/tmp, in which applications cache temporary data that is
expendable. Refer to the nodelayed option for information on
disabling delayed metadata updates. Synchronously flushes
metadata updates to disk. This is the default behavior.
By default, to maintain file system consistency, UFS metadata
(such as inode, directory, and indirect blocks) is updated syn‐
chronously, which ensures that the UFS file system is consis‐
tent at all times and no data is lost if your system crashes.
However, it can affect file system performance. Refer to the
delayed option for information on disabling synchronous metadata
updates to improve performance. Prevents excessive asynchronous
I/O from overloading the device queue, which can affect response
time for processes waiting for I/O operations to complete. To
use this argument, you must enable smooth sync.
See the EXAMPLES section for usage examples.
NFS mount - o Arguments
The following arguments are valid for NFS file system: Allows access to
block and character-special devices. Disallows access from the file
system to either block or character-special devices. Allows read/write
access. Allows read-only access. Allows set-user-ID execution. Pro‐
hibits set-user-ID execution. Causes all writes to be written immedi‐
ately to disk as well as to the buffer cache. Specifies that writes
may return before data is written to disk. Allows binary execution.
Prohibits binary execution. New files inherit the parent directory's
group ID. This is the default and matches BSD's semantics. SVID 3
semantics applied. For example, if the parent directory's mode bits
include IS_GID, then the new file will inherit the parent's group ID.
If IS_GID is off, then it inherits the process group ID. Retries in
the background, if the first mount attempt fails. Retries in the fore‐
ground. Sets the number of mount failure retries to n. Sets the read
buffer size to n bytes. Sets the write buffer size to n bytes. Sets
the initial NFS timeout period for UDP mounts to n tenths of a second.
NFS continually adjusts the timing as a function of network response
time. Sets the maximum value, in seconds, that is allowed between
request transmissions. (UDP mounts only) Sets the number of NFS
retransmissions to n. Allows hard mounted file system operations to be
interrupted. Prevents hard mounted file system operations from being
interrupted, unless the thread is terminated (for example by a SIGKILL
or an AST). Returns an error if the server does not respond. Retries
the request until the server responds. Usually, the mount command
tries to use Version 3 of the NFS protocol. If the server does not
support Version 3, then the mount command retries the mount using Ver‐
sion 2. Specifying -o nfsv2 forces the mount command to use NFS Ver‐
sion 2. NFS Version 3 is an enhanced version of the NFS protocol that
provides 64-bit file access, as well as features designed to improve
performance and correctness.
Alternatively, you can use the vers=2 argument. Tries to use
Version 3 of the NFS protocol. If the server does not support
it, Version 2 is used. This is the default.
Alternatively, you can use the vers=3 argument. Specifies the
network transport: udp or tcp.
Specify udp to use UDP as the network transport. This is sup‐
ported by all known NFS servers. UDP works best in local, fast,
and reliable environments. The mount will fail if the server
does not support NFS over UDP. The proto=udp syntax is the
Specify tcp to use TCP as the network transport. This is sup‐
ported by some vendors, but not all. TCP works better than UDP
in high-loss, congested networks, and is the only way to use NFS
over the Internet. The mount will fail if the server does not
support NFS over TCP.
The -o tcp syntax is compatible with 4.4 BSD syntax, while the
proto=tcp syntax is compatible with Solaris 2.4 syntax. Sets
the server IP port number to the value of n. The default is to
query the portmap daemon on the server for the port number
(which is almost always 2049). This argument is useful only
when the server is not running the portmap daemon or is running
multiple NFS servers. Both of these situations are very rare.
Allows the use of extended attributes (property list) including
access control lists (ACLs) on this file system. The NFS server
exporting this file system must be running the proplistd daemon.
See proplist(4), acl(4), and proplistd(8) . Specifies the ver‐
sion of the NFS protocol. You can specify either Version 3 or
Usually, the mount command tries to use Version 3 of the NFS
protocol. If the server does not support Version 3, then the
mount command retries the mount using Version 2. Specifying
vers=2 forces the mount command to use NFS Version 2. NFS Ver‐
sion 3 is an enhanced version of the NFS protocol that provides
64-bit file access, as well as features designed to improve per‐
formance and correctness.
Alternatively, you can use the nfsv2 or nfsv3 argument.
For NFS, the defaults are fg, retry=10000, timeo=11, maxtimo=20,
retrans=4, hard, and intr. Defaults for rsize and wsize are set by the
The bg argument causes mount to run in the background if the server's
mountd does not respond. The mount command attempts each request retry
times before giving up. Once the file system is mounted, each NFS
request made in the kernel waits timeo tenths of a second for a
response. If no response arrives, the timeout period is multiplied by 2
and the request is retransmitted.
When retrans retransmissions have been sent with no reply, a soft
mounted file system returns an error on the request and a hard mounted
file system retries the request at maxtimo intervals. File systems that
are mounted rw (read/write) should use the hard argument. The number
of bytes in a read or write request can be set with the rsize and wsize
Using the mount command with the -t nfs option may cause it to touch
the /etc/exports file. If the/etc/exports file has been manually cre‐
ated, you should ensure that it has bin:bin owner:group ownership.
NFS Update Visibility mount - o Arguments
These arguments control how quickly you see updates to a file or direc‐
tory that has been modified by another host. Increasing these values
gives you slightly better performance. Decreasing the values decreases
the time it takes for you to see modifications made on the other host.
If you are the only person modifying files under this mount point, you
should increase these values. Holds cached directory attributes for at
least n seconds. Holds cached directory attributes for no more than n
seconds. The maximum value you can specify is 3600. Holds cached file
attributes for at least n seconds. Holds cached file attributes for no
more than n seconds. The maximum value you can specify is 3600. Sets
all four attributes' cache timeout values to n. Sets no attribute
caching. This argument is equivalent to actimeo=0. Sets no fresh
attribute when opening a file.
The NFS update visibility argument defaults are acdirmin=30,
acdirmax=60, acregmin=3, and acregmax=60.
CDFS mount - o Arguments
The following arguments are valid for the CD-ROM File System (CDFS):
Ignores the permission bits, if present, and defaults all file and
directory permissions to the value 0555, with a zero User ID (UID,
owned by root). Files and directories recorded on an ISO 9660-formatted
file system might or might not have permission bits. This setting is a
default argument because the permissions on most existing ISO 9660-for‐
matted CD-ROMs do not map to the UID scheme that is used. Uses the on-
disk permission bits, if present. If a file or directory is not
recorded with permission bits, the default 0555 is used. Strips off
the extension (;#) from the version string if a file recorded on an ISO
9660-formatted file system or a file system formatted by the High
Sierra Group contains a version string. File and directory names are
displayed in lowercase letters and case-insensitive name matching is
performed. Use this argument if you are mounting a CD-ROM containing
MS-DOS applications. Uses the Rock Ridge Interchange Protocol (RRIP)
extensions to ISO 9660 (if present on the file system) to provide
mixed-case file names, device special files, and other attributes for
files on the file system. This setting is a default argument. If there
are no RRIP extensions on the file system, the file system will be
mounted and the argument will be ignored. Turns off the Rock Ridge
Interchange Protocol (RRIP) extensions to ISO 9660 for files on the
file system. If there are RRIP extensions on the file system, the file
system will be mounted and the extensions will be ignored. Uses the
Microsoft Joliet formatted CD-ROM media, which provides long, mixed-
case file names. Turns off Microsoft Joliet formatted CD-ROM media.
Uses the ISO 9660 uppercase 8.3 formatted file system. This is the
default if no other file formats are found. Uses verbose messages in
The defaults for CDFS are ro, nodev, defperm, and rrip.
CD-ROMs can contain several formats to support different platforms and
operating systems. If you know which format you require (RRIP, Joliet,
or ISO9660) specify the appropriate qualifier to the -o option.
If you do not specify options for file name formats on the command
line, the mount command automatically tests for the presence of formats
and mounts it by default, according to the following rules of prece‐
dence: Check if Rock Ridge Interchange Protocol (RRIP) extensions are
found on the CD-ROM, if yes, mount as -t cdfs -o rrip. If RRIP exten‐
sions are not found, check if the media has Microsoft Joliet formatted
file names. If yes, mount as -t cdfs -o joliet. If neither of the
above were found, the mount command defaults to ISO 9660 format.
If you specify one or more exclusive qualifiers, such as -o norrip, the
mount command does not test for the presence of that format, and
defaults to the next highest precedent.
If a specifically-requested format is not found and other formats are
not excluded, the mount command will attempt to mount the next highest
precedent. For example, you attempt to mount a CD-ROM specifying -o
joliet format but the CD-ROM does not contain that format. Unless you
specifically requested -o norrip, the mount command will attempt to
mount RRIP. If RRIP is not found, the mount command defaults to ISO
FFM mount - o Arguments
The following arguments are valid for the File-on-File-Mounting (FFM)
file system: Allows two separate files to have identical contents, sep‐
arate names, and separate file descriptors. (Do not confuse this clone
with an AdvFS clone fileset.)
Specifies one or more file systems. How you specify a file system
depends on whether it is UFS or NFS or AdvFS.
To specify a UFS file system, enter the name of its block device
special file. For example: /dev/disk/dsk3c. The mount command
returns an error if you try to mount the file system on a parti‐
tion that is already in use.
To specify an NFS file system, specify the host and path name in
either of these formats: host:path or path@host.
To specify an AdvFS fileset, enter the name of the file domain,
a pound-sign(#) character, and the name of the fileset. For
example: root_domain#root. Specifies one or more directories.
The directory must exist before you use the mount command. When
the command is successful, the directory becomes the name of the
newly mounted root directory, its mount point.
When specified with the umount command, the directory must not
be in use. Use the pwd command to check your present working
directory. If you or another user is in the mounted directory or
in any directory in its hierarchy, you must switch to a differ‐
ent directory. Likewise, if you are using files in the mounted
directory, you must close the files to successfully unmount the
Use the mount command to make a file system available for use, or
mounted. Use the umount command to make a file system unavailable for
use, or unmounted.
Use the mount command with the -q option to determine which file system
or file systems are found on an unmounted CD or DVD device. You can
either read the command output or interpret the exit code to determine
which file system is found, and thus, how it should be mounted.
The format used in the mount command determines the format returned by
the getfsstat and getmntinfo commands.
If the mount command is invoked with only a file-system or directory
operand specified, the command searches the /etc/fstab file for an
entry whose file-system or directory field matches the argument speci‐
fied with the command.
For example, if the line /dev/disk/dsk0g /usr ufs rw 1 1 is specified
in the /etc/fstab file, both of these two commands, mount /usr and
mount /dev/disk/dsk0g are equivalent to the following command: # mount
The umount command announces to the system that the file system file-
system previously mounted on directory should be removed. Either the
file system name or the directory mount point can be specified in the
To use the mount and unmount commands, you must be the root user, with
the following exceptions: If NFS file systems have been explicitly
exported to allow nonroot users to mount the file system. Refer to the
-n option of mountd(8) for more information. If a CD-ROM is mounted
(by specifying the -t cdfs option) and the user owns the mount point.
The mount command also lets you mount an ISO 9660- or HSG-formatted
file system onto a directory.
No more than one user at a time should mount a disk partition with
read/write access or the file system might become corrupted.
If the directory on which a file system is to be mounted is a symbolic
link, the file system is mounted on the directory to which the symbolic
link refers, rather than on top of the symbolic link itself.
When you boot to single-user mode, the root file system is mounted with
read-only access. If you want to modify a file, you must change the
options on the root file system to read/write. You can do this with the
following command: # mount -u /
If your /etc/fstab file is corrupted, you can mount the root file sys‐
tem with the following command: # mount -u /dev/disk/dsk??/
You must be the root user to mount a UFS file system. By default, the
maximum number of UFS mounts is 1,000. However, you can modify this
value by using the sysconfig command. For example: # sysconfig -r vfs
The default for CDFS is to not allow access to device special files
(argument nodev) because the device numbers recorded on a disc using
RRIP extensions might not match the device numbers used by the operat‐
ing system. If you want to allow device access, mount the file system
with the dev argument and use the cddevsuppl command to map the device
numbers of the device special files on the disc to new device numbers
used by the operating system.
The mount command attempts to dynamically load the cdfs kernel modules
if they are not statically built into the running kernel. However, you
must be the root user to dynamically load the cdfs kernel modules.
Other users receive the following error should they attempt the opera‐
tion: mount: super user privileges required to load cdfs module
All other errors that could occur as the cdfs kernel modules are being
dynamically loaded produce the following error message: mount: Can't
load cdfs module
Refer to cdfs(4) for information on the correct system configuration
options to set before using CDFS.
NFS mounts can fail due to authentication requirements on the server.
For example, a “Client credential too weak” message is returned if a
user attempts to mount and the server only allows root user mounting.
A “Server rejected credential” message is returned if the server is not
able to resolve the client's IP address.
If your workstation has multiple network interfaces, the server must be
able to resolve all IP addresses from which it might receive mount
requests. See mountd(8) or the Network Administration: Services manual
for more information.
When you mount the first fileset in an AdvFS domain, AdvFS determines
whether or not it can access all data in all volumes of that domain.
If AdvFS determines that the size of any volume in the domain is actu‐
ally smaller than the size recorded for that volume in the domain's
metadata, there are two possible outcomes: The mount succeeds, but in
read-only mode. In this case, AdvFS is able to read the last currently
in-use block on the volume. A message similar to the following is dis‐
played: Actual size of virtual disk /dev/vol/vol01 is 100352 blocks but
recorded size is 102400 blocks. Mounting fileset staff#grads in read-
only mode. The mount fails. In this case, AdvFS cannot read the last
currently in-use block on the volume. A message similar to the follow‐
ing is displayed: Actual size of virtual disk /dev/vol/vol01 is 100352
blocks but recorded size is 102400 blocks. Cannot read essential data
on /dev/vol/vol01. Corrupted volume found; failing mount of
staff#grads. staff#grads on /grads: I/O error
When you attempt to mount an AdvFS fileset in an AdvFS domain, the num‐
ber of volumes pointed to by the /etc/fdmns/dmn_name links must equal
the number of volumes in the domain. If you attempt to mount an AdvFS
file system with an incorrect number of volumes, the following message
will appear on the console: # Volume count mismatch for domain
dmn_name. dmn_name expects 2 volumes, /etc/fdmns/dmn_name has 1 links.
To correct the problem, you must match the number of volumes and then
mount them. See advscan(8) for more information.
Smoothsync increases efficiency in the part of the file system that
uses the disks for writing dirty pages. Prior to smoothsync, dirty
pages were scheduled for writing every 30 seconds by the update daemon.
The smoothsync model schedules each page for writing after that page
has been dirty for the smoothsync_age period (default 30 seconds).
This allows all buffers to age the full smoothsync_age period, versus
an average of 15 seconds with the update daemon model. This approach
also distributes the requests made of the disk subsystem evenly across
the smoothsync_age period. The update daemon model submits all the I/O
The smoothsync_age period can be set using sysconfig. A value of 0
An alternate smoothsync policy can be enabled on a file system basis by
mounting with the smsync2 flag. With this policy, a page is not sched‐
uled for writing until it is dirty and unmodified for the last smooth‐
sync_age period. For example, suppose you have an application that
keeps updating the same page repeatedly. With smsync2 enabled, until
the page has been idle (unchanged) in memory for the entire smooth‐
sync_age period, it will not be written to disk. Therefore, if the
smoothsync_age is 30 seconds, and your application updates the page in
memory every 10 seconds, the page might not be written to disk for a
very long time.
While this policy might further decrease I/O load, it is appropriate
only for file systems or applications in which additional data loss is
acceptable if the system crashes.
The mount and umount commands support mount point argument pathnames of
up to MNAMELEN, which includes the null terminating character. MNAME‐
LEN can be up to 90 characters long, including the null terminating
Before you can use the FFM file system, you must configure the kernel
option FFM_FS into the kernel.
Success. An error occurred.
Use the following chart to determine which file systems are on the
device from the exit code when you invoke the mount command with the -q
UFS CDFS DVDFS
3 X X
5 X X
6 X X
7 X X X
The following sections describe some warnings and errors produced by
Overlapping Partitions Warnings
The following warning messages about overlapping partitions are dis‐
played only if you use the -v option. Warning: partition special-
device and overlapping partition(s) are marked in use in the disklabel.
The specified partition overlaps with another partition or par‐
titions that have the fstype field set. Warning: partition(s)
which overlap special-device are marked in use in the disklabel.
The partition overlaps another partition or partitions that have
the fstype field set. Warning: the disklabel for special-device
does not exist or is corrupted.
The device specified either does not have a disk label or the
disk label has been corrupted. Warning: unable to check spe‐
cial-device against active AdvFS domains because the directory
/etc/fdmns seems to be missing or wrong.
There was a failure when checking the overlap with AdvFS
domains. The failure is with /etc/fdmns or /etc/fdmns/dom, or an
active domain does not exist. Warning: unable to check special-
device against active swap devices because special swap files
A failure occurred when checking the overlap with active swap
devices. The special device files associated with active swap
devices are invalid. Warning: unknown overlap condition errno
encountered for partitionspecial-device.
An unknown overlap condition was encountered for the specified
device. Error: partition special-device is marked 'unused'
The fstype in the disk label temporarily is set and will revert
with the following messages when you unmount the file using
umount: Warning: partition /dev/disk/dsk5c was detected as
marked unused. Warning: partition /dev/disk/dsk5c temporarily
set to /
'FS_BSDFFS' 4.2BSD Fast File System. Warning: Please use
disklabel to correct this condition.
Overlapping Partitions Errors
The following are fatal error messages associated with overlapping par‐
titions. Error: File system type fstype is invalid or not installed.
The file system type specified is not resident in the kernel or
is otherwise inaccessible. Error: an overlapping partition is
A partition that overlaps the specified partition is open.
Error: special-device is an invalid device or cannot be opened.
The specified device is invalid and an overlapping partition is
open. Error: special-device contains a fstype file system.
The specified partition and overlapping partitions have the
fstype field set. Error: Unknown severe error errno encountered
An unknown overlap condition was encountered for the specified
To mount a local disk, enter: % mount /dev/disk/dsk0g /usr To mount an
AdvFS fileset, enter either of the following commands: % mount -t advfs
% mount usr_dmn#user1 /usr/user1 To mount all ufs file systems,
enter: % mount -at ufs To mount a remote file system, enter
either of the following commands: % mount -t nfs serv:/usr/src
% mount -t nfs /usr/src@serv /usr/src To mount a remote file
system with a hard mount, enter: % mount -o hard serv:/usr/src
To mount an ISO 9660-formatted or HSG-formatted file system from
block device /dev/disk/cdrom3c onto the local directory /cdfs
with the file version strings stripped off, enter either of the
following commands: % mount -t cdfs -o noversion
% mount -o noversion /dev/disk/cdrom3c /cdfs To mount a UFS
CD-ROM (for example, the installation CD-ROM) from block device
/dev/disk/cdrom3c onto the local directory cdrom, enter either
of the following commands: % mount -r /dev/disk/cdrom3c /cdrom
% mount -o ro /dev/disk/cdrom3c /cdrom To mount the joliet-for‐
matted file system on a multi-formatted file system from block
device /dev/disk/cdrom3c onto the local directory /cdfs enter
the following: % mount -t cdfs -o joliet /dev/disk/cdrom3c /cdfs
To unmount the file system mounted on the /mnt local directory,
enter the following command: % umount /mnt To unmount all NFS
file systems, enter the following command: % umount-A -t nfs To
unmount all file systems exported from host2, enter the follow‐
ing command: % umount-h host2 To use the delayed metadata
option, use commands similar to the following examples: To
enable delayed metadata updates and improve performance (at the
risk of data loss), use a command similar to the following: #
mount -o delayed /dev/disk/dsk3c /tmp_files
To enable delayed metadata update on a file system that is
already mounted, use a command similar to the following: # mount
-u -o delayed /tmp_files
Any options that were in force are turned off by this command.
Therefore, you must also reenter all required mount options when
you use the -o delayed option on a mounted file system To dis‐
able the delayed metadata update option, use a command similar
to the following: # mount -u -o nodelayed /tmp_files
Any options that were in force are turned off by this command.
Therefore, you must also reenter all required mount options when
you use the -o nodelayed option on a mounted file system. To
view which mount option is in operation for a given file system,
use the mount command without arguments, as follows: # mount
/dev/disk/dsk3c on /tmp_files type ufs (rw, delayed)
Note that the word delayed appears in the mount options list at
the end of the output from the mount command. To determine how
the device /dev/rdisk/cdrom0c can be mounted, enter the follow‐
ing command: # mount -q /dev/rdisk/cdrom0c /dev/rdisk/cdrom0c
can be mounted as: CDFS DVDFS
Specifies the command path. Specifies the command path. Contains
static information about file systems.
Commands: cddevsuppl(8), extendfs(8), mfs(8), mountd(8), nfsd(8), pro‐
Functions: mount(2), mount(2sv), umount(2), umount(2sv), umount(3)
Files: advfs(4), cdfs(4), fstab(4), mountdtab(4)
System Administration, Network Administration: Services, Cluster Admin‐