mount_vxfs(1M)mount_vxfs(1M)NAMEmount_vxfs - mount a VxFS file system
SYNOPSIS
[ generic_options ] specific_options ]
{ special | mount_point }
[ generic_options ] specific_options ]
special mount_point
DESCRIPTION
attaches special, a removable file system, to directory, a directory on
the file tree. (This directory is also known as the mount point).
directory, which must already exist, becomes the name of the root of
the newly mounted file system. If you omit either special or direc‐
tory, attempts to determine the missing value from an entry in can be
invoked on any removable file system, except /. special and directory
must be given as absolute path names.
notifies the system that special, a VxFS block special device, is
available to users from mount_point, which must exist before is
invoked. mount_point becomes the name of the root of the newly mounted
file system special.
Unlike some file system commands, you cannot specify multiple options
to only the last option is used.
If you invoke with no arguments, it lists all the mounted file systems
from the mounted file system table,
The command notifies the system that special, a VxFS block special
device, is available to users from mount_point, which must exist before
is invoked. mount_point becomes the name of the root of the newly
mounted file system special.
Multiple options can be specified in a comma-separated list.
Only a privileged user can mount file systems.
Use and only on cluster-mounted file systems and determine cluster
write and failover capabilities respectively. provides improved con‐
currency for applications employing parallel I/O.
The policy behavior for cluster mounts is different from local mounts.
See the option description for details.
Be careful when accessing shared volumes with other utilities, such as
that can write data to disk. It is possible to destroy data being
accessed from other nodes.
The and options are not supported on cluster file systems.
OPTIONS
generic_options
Supported by the generic command. See mount(1M).
Specifies the VxFS file system type.
Specifies the VxFS-specific options in a comma-separated list.
The available options are:
Clears all data extents before allocating them to a file
(requires synchronous zeroing of certain newly allocated
extents). This prevents uninitialized data from being
present in a file at the time of a system crash.
Mounts the Storage Checkpoint of a VxFS file system.
ckpt_name is the name of a file system Storage Check‐
point previously created by the command (see fsckp‐
tadm(1M)). mount_point is the directory on which to
mount the Storage Checkpoint. special is the Storage
Checkpoint pseudo device. Storage Checkpoints are
mounted on pseudo devices that do not appear in the sys‐
tem name space. The pseudo devices are created and
exist only while the Storage Checkpoint is mounted. A
Storage Checkpoint pseudo device name has the following
format:
device_path:ckpt_name
Storage Checkpoints are mounted read-only by default,
but you can mount or remount them as writable using the
option. A file system must be mounted before any of its
Storage Checkpoints can be mounted. A file system can
be unmounted only after all of its Storage Checkpoints
are unmounted.
To mount a Storage Checkpoint in shared mode on a clus‐
ter file system, you must also specify the option (see
below).
Mounts a file system in shared mode.
special must be a shared volume in a Cluster Volume Man‐
ager (CVM) environment. Other nodes in the cluster can
also mount special in shared mode. A local mount cannot
be remounted in shared mode and shared mount cannot be
remounted in local mode.
The first node to mount special is called the primary
node. The primary node handles intent logging for the
cluster. Other nodes are called secondary nodes. A
secondary writable node is not allowed if the primary
node is mounted as read-only
Alters the caching behavior of the file system for
O_SYNC and O_DSYNC I/O operations.
The value handles any reads or writes with the O_SYNC or
O_DSYNC flags as if the VX_DIRECT caching advisory is
set.
The value handles any writes with the O_SYNC flag as if
the VX_DSYNC caching advisory is set. It does not mod‐
ify behavior for writes with O_DSYNC set.
The value handles any reads or writes with the O_SYNC or
O_DSYNC flags as if the VX_UNBUFFERED caching advisory
is set.
The value delays O_SYNC or O_DSYNC writes so that they
do not take effect immediately.
If the or value is set and a file is written to using a
file descriptor with the O_SYNC or O_DSYNC flag set, the
equivalent of an call is performed on the final close of
the descriptor.
The value delays O_SYNC or O_DSYNC writes so that they
do not take effect immediately. With this option, VxFS
changes O_SYNC or O_DSYNC writes into delayed writes.
No special action is performed when closing a file.
This option effectively cancels data integrity guaran‐
tees typically provided by opening a file with O_SYNC or
O_DSYNC.
The cluster read-write option allows
asymmetric mounts; that is, you can mount a specified
cluster file system in read-only or read-write mode
independently of the other shared file system nodes.
must be specified with the option. Without specifying
the default functionality of the cluster mount is
retained; the read-write capability of cluster secon‐
daries are the same as the cluster primary. You can use
the in conjunction with or as shown in the following
mount compatibility matrix:
Secondary
------- ----------------------------------
Primary ro rw ro,crw rw,crw
------- ----------------------------------
ro yes no no no
rw no yes yes yes
ro,crw no yes yes yes
rw,crw no yes yes yes
If the primary is mounted with or as shown in the first
column, the secondary read and write capabilities can
still be set independently. For a cluster mount, on the
primary enables cluster-wide read-write capability.
The read and write capabilities can be changed from its
original setting to another using the option. The read
and write capabilities can be changed according to the
following matrix:
------- ----------------------------------
From/To ro rw ro,crw rw,crw
------- ----------------------------------
ro no yes yes yes
rw no yes no yes
ro,crw no yes yes yes
rw,crw no yes no yes
If a cluster file system is mounted read-write the
underlying disk group must have the activation mode
attribute set to
If a cluster file system is mounted and the disk group
activation mode is that cluster file system can never be
a primary, and must be mounted (see the option below).
See the and vxdg(1M) for more information on disk acti‐
vation modes.
Generally, VxFS does O_SYNC or O_DSYNC writes by
logging the data and the time change to the inode If the
option is used, the logging of synchronous writes is
disabled; O_SYNC writes the data into the file and
updates the inode synchronously before returning to the
user.
Sets the policy for handling I/O errors on a mounted file
system.
Multiple error policies were implemented in VxFS to han‐
dle evolving storage technologies for which a single
approach is no longer adequate. is the default mount
option for local mounts. is the default mount option
for cluster mounts.
I/O errors can occur while reading or writing file data,
or while reading or writing metadata. The file system
can respond to these I/O errors either by halting or by
gradually degrading. provides four policies that deter‐
mine how the file system responds to the various errors.
All four policies limit data corruption, either by stop‐
ping the file system or by marking a corrupted inode as
bad.
The following matrix shows how the file system responds
to the various errors depending on the policy set:
file file metadata metadata
read write read write
----------------------------------------
disable | disable | disable | disable | disable |
----------------------------------------
nodisable | degrade | degrade | degrade | degrade |
----------------------------------------
wdisable | degrade | disable | degrade | disable |
----------------------------------------
mwdisable | degrade | degrade | degrade | disable |
----------------------------------------
If is selected, VxFS disables the file system after
detecting any I/O error. You must then unmount the file
system and correct the condition causing the I/O error.
After the problem is repaired, run and mount the file
system again. In most cases, replay is sufficient to
repair the file system. A full is required only in
cases of structural damage to the file system's meta‐
data. Select in environments where the underlying stor‐
age is redundant, such as RAID-5 or mirrored disks.
If is selected, when VxFS detects an I/O error, it takes
steps (sets the appropriate error flags), to contain the
error, but continues running. Note that the "degraded"
condition indicates possible data or metadata corrup‐
tion, not the overall performance of the file system.
For file data read and write errors, VxFS sets the
VX_DATAIOERR flag in the super-block. For metadata read
errors, VxFS sets the VX_FULLFSCK flag in the super-
block. For metadata write errors, VxFS sets the
VX_FULLFSCK and VX_METAIOERR flags in the super-block
and may mark associated metadata as bad on disk. VxFS
then prints the appropriate error messages to the con‐
sole (see the for information on what actions to take
for specific errors).
You should stop the file system as soon as possible and
repair the condition causing the I/O error. After the
problem is repaired, run and mount the file system
again.
Select if you want to implement the policy that most
closely resembles the previous VxFS error handling pol‐
icy.
If (write disable) or (metadata-write disable) is
selected, the file system is disabled or degraded, as
shown in the matrix, depending on the type of error
encountered. Select or for environments where read
errors are more likely to persist than write errors,
such as when using non-redundant storage.
Note: If there is serious damage to the file system, or
there is structural corruption of file system metadata,
VxFS marks the file system for full regardless of which
I/O error policy is in effect.
Behavior on cluster file systems is somewhat different.
If the policy selected is the file system is disabled
only on the node where the I/O error occurs. The file
system is still accessible from the other nodes. If the
I/O error is on the CFS primary, a new primary is
elected from the remaining nodes and the original pri‐
mary becomes a secondary.
is the recommended policy for cluster file systems.
With any other policy, a metadata I/O error can mark the
file system for a full file system check. If the CFS
primary subsequently fails, the other nodes in the clus‐
ter cannot take over the primaryship, thereby disabling
access to the file system from all nodes in the cluster.
Note: If the CVM disk detach policy (the way unusable
disks in a shared disk group are detached) is the I/O
error policy must be disable.
These options do not turn largefiles capability on
and off (use or to set and clear the largefiles flag),
but they do verify whether a file system is largefiles
capable. If is specified and the mount succeeds, the
file system does not contain any files two gigabytes or
larger, and such files cannot be created. If is speci‐
fied and the mount succeeds, the file system can contain
files two gigabytes or larger, and large files can be
created. For a mount to succeed, the option must match
the largefiles flag as specified by or
Note: Be careful when enabling large file system capa‐
bility. System administration utilities such as backup
may experience problems if they are not large file
aware.
Controls the timing of flushing the VxFS intent log and other
metadata
to disk, which affects when operations are guaranteed
persistent after a system failure. The default is
In the following description, the term "effects of sys‐
tem calls" refers to changes to file system data and
metadata caused by the system call, excluding changes to
(see stat(2)).
In mode, all system calls other than and are guaranteed
to be persistent once the system call returns to the
application.
In mode, the effects of most system calls other than and
are guaranteed to be persistent approximately 3 seconds
after the system call returns to the application. Con‐
trast this with the behavior of most other file systems
in which most system calls are not persistent until
approximately 30 seconds or more after the call has
returned.
In mode, the effects of system calls have persistence
guarantees that are similar to those in mode. In addi‐
tion, enhanced flushing of delayed extending writes is
disabled, which results in better performance but
increases the chances of data being lost or unitialized
data appearing in a file that was being actively written
at the time of a system failure. This mode is only rec‐
ommended for temporary file systems.
In and mode, the system call flushes the source file to
disk to guarantee the persistence of the file data
before renaming it. In both modes, the is also guaran‐
teed to be persistent when the system call returns.
This benefits shell scripts and programs that try to
update a file atomically by writing the new file con‐
tents to a temporary file and then renaming it on top of
the target file.
In all cases, VxFS is fully POSIX compliant. The
effects of the and system calls are guaranteed to be
persistent once the calls return. The persistence guar‐
antees for data or metadata modified by or are not
affected by the logging mount options. The effects of
these system calls are guaranteed to be persistent only
if the O_SYNC, O_DSYNC, VX_DSYNC, or VX_DIRECT flag, as
modified by the mount option, has been specified for the
file descriptor.
The behavior of NFS servers on a VxFS file system is
unaffected by the and mount options. In all cases, VxFS
complies with the persistency requirements of the NFS v2
and NFS v3 standard.
The performance of some storage devices (specifically,
devices using the read-modify-write feature) improves if
the writes are issued in one or more multiples of a par‐
ticular size. When a file system is mounted with the
option, VxFS writes the intent log in at least size
bytes, or a multiple of size bytes, to obtain the maxi‐
mum performance from such devices. The values for size
can be 1024, 2048, or 4096. The default value is the
sector size of the device. The option is supported only
on local mounts.
Alters the caching behavior of the file system.
The value handles any reads without the O_SYNC flag, or
any writes without the O_SYNC flag, VX_DSYNC, VX_DIRECT,
and VX_UNBUFFERED caching advisories, as if the
VX_DIRECT caching advisory was set.
The value handles any writes without the O_SYNC flag, or
one of the VX_DIRECT, VX_DSYNC, and VX_UNBUFFERED
caching advisories, as if the VX_DSYNC caching advisory
was set.
The value handles any reads without the O_SYNC flag, or
any writes without the O_SYNC flag, VX_DSYNC, VX_DIRECT,
and VX_UNBUFFERED caching advisories, as if the
VX_UNBUFFERED caching advisory was set.
For the and values, when the final close of a file
descriptor referencing a file is performed, the equiva‐
lent of an call is performed.
The value disables delayed extending writes, trading off
integrity for performance. If is used in conjunction
with newly allocated extents are not zeroed. If the
system crashes, uninitialized data may appear in files
that were being written at the time of a system crash.
See vxfsio(7) for an explanation of VX_DIRECT, VX_DSYNC,
and VX_UNBUFFERED.
Directs the file system to ignore file access time updates
except when they coincide with updates to or (see
stat(2)). By default, the file system is mounted with
access time recording. You can use the option to reduce
disk activity on file systems where access times are not
important.
Allows the file system to be mounted explicitly.
That is, the option will not cause the file system to be
mounted. This option is normally used for filesystems
listed in which should not be mounted automatically at
boot time.
The option is for distributed applications that read and
write to the same file simultaneously from one or more
cluster nodes. delays updating the file modification
time in the specified cluster file system. Updating
file modification and change times are not synchronized
within the cluster, which eliminates serializing two
updates and improves concurrency. Use this option in
high-performance computing (HPC) environments when an
application does not require consistent, cluster-wide
file modification times. The option operates only on
cluster mounted file systems See the for more informa‐
tion on parallel I/O.
Enables or disables the VERITAS Quick I/O for Databases
option for the given file system. Quick I/O is avail‐
able as a licensed feature of VxFS. By default, enables
Quick I/O on the file system. If Quick I/O is not
available, mounts the file system without Quick I/O. If
is specified, but the feature is not licensed, prints an
error message and terminates without mounting the file
system. If is specified, disables Quick I/O even if the
license is installed.
For cluster file systems, is also the default if a Quick
I/O license is present.
Enables disk quotas.
The option is valid only on file systems that are
mounted read/write
To turn on user quotas, there must be a file named owned
by root in the file system root directory. If this file
does not exist, a file is created. The file stores
usage limits for each user.
VxFS maintains quota information in a private area of
the file system. If the file system is mounted with
quotas enabled, and the file system was previously
mounted with quotas disabled and was modified, the quota
information is rebuilt. This may take awhile depending
on the amount of information to rebuild. See
edquota(1M) for details on how to create and modify
usage limits in the quotas file.
Changes the mount options for a mounted file system.
In particular, changes the logging and caching policies.
It also changes a file system from read-only to
read/write.
cannot change a file system from read/write to read-
only, nor can it set the or attributes.
Read-write or read-only.
The default is
Mounts a shared file system as a secondary only.
A secondary-only file system cannot assume the primary‐
ship for the specified shared file system. For a mount
with the option to succeed, primary must already be
mounted. must be specified with the option. The option
overrides any policy that was set using the command (see
fsclustadm(1M)). This option can be set or reset using
the option. A remount with fails if the file system
node is already the primary for the file system.
Mounts the file system as a snapshot of
filesystem, where filesystem is either the directory on
which a VxFS file system is mounted, or the block spe‐
cial file containing a mounted VxFS file system.
On cluster file systems, snapshots can be created on any
node in the cluster, and backup operations can be per‐
formed from that node. The snapshot of a cluster file
system is accessible only on the node where it is cre‐
ated; that is, the snapshot file system itself cannot be
cluster mounted. See the for details on creating snap‐
shots on cluster file systems.
Note: The filesystem argument cannot refer to a multi-
volume file system unless the file system contains only
one volume. The special argument cannot refer to a vol‐
ume set.
Used in conjunction with
size is the size in sectors of the snapshot file system
being mounted. This option is required only when the
device driver cannot determine the size of snapof_spe‐
cial, and defaults to the entire device if not speci‐
fied.
is honored or ignored on execution.
The default is
When VxFS is the default boot file system
on HP-UX, there can be no intent log replay during the
initial stages of the boot process. To ensure data and
metadata consistency during the boot process, the option
flushes all metadata updates to disk before returning
from a system call. The option therefore enables VxFS
to approximate the behavior of a file system with no
intent logging functionality. The option automatically
enables the and options. It is advisable to specify the
mount option with must be explicitly specified when
remounting the file system.
The and mount options do not operate with The tranflush
option does not operate on read-only file systems or
cluster file systems.
EXAMPLES
To mount a Storage Checkpoint of a file system, first mount the file
system, then mount the Storage Checkpoint:
mount -F vxfs /dev/vx/dsk/fsvol /fsdir
mount -F vxfs -ockpt=myckpt /dev/vx/dsk/fsvol:myckpt /ckptdir
To unmount a file system, unmount the Storage Checkpoint first:
umount /ckptdir
umount /fsdir
To mount a Storage Checkpoint of a cluster file system on a VERITAS
Volume Manager volume:
mount -F vxfs -o cluster,ckpt=ckpt_name \
/dev/vx/dsk/dg_name/volname:ckpt_name /ckpt_mount_point
To have Storage Checkpoints mounted automatically when the system
reboots, you can list them in the file as in the following example:
/dev/vx/dsk/fsvol /fsdir vxfs defaults 0 2
/dev/vx/dsk/fsvol:myckpt /ckptdir vxfs ckpt=myckpt 0 0
FILES
Table of mounted file systems.
SEE ALSOqiomkfile(1),
edquota(1M),
fsadm_vxfs(1M),
fsck_vxfs(1M),
fsckptadm(1M),
fsclustadm(1M),
mkfs_vxfs(1M),
mount(1M),
setmnt(1M),
vxdg(1M),
vxumount(1M),
fdatasync(2),
fsync(2),
setuid(2),
stat(2),
fstab(4),
fs_vxfs(4),
mnttab(4),
vxfsio(7),
mount_vxfs(1M)
