mount_vxfs(1M)
mount_vxfs - mount a VERITAS File System
Synopsis
mount [-F vxfs] [generic_options] [-r] [-o specific_options] {special | mount_point}
mount [-F vxfs] [generic_options] [-r] [-o specific_options] special mount_point
Description
mount notifies the system that special, a vxfs block special device, is available to users from mount_point, which must exist before mount is called. mount_point becomes the name of the root of the newly mounted special.
Options
- generic_options
- Supported by the generic mount command.
- -F vxfs
- Specify the vxfs file system type.
If -F vxfs is not specified
heuristics similiar to those used by
fstyp(1M)
are used to determine the file system type.
This command executes faster if it is not required
to autodetect file system types. If possible, specify
-F vxfs
- -r
- Mount the file system read-only.
- -o
- Specify the vxfs file system specific options in a comma-separated list. The available options are:
- rw | ro
- Read/write or read-only. The default is rw.
- suid | nosuid
- setuid is honored or ignored on execution
(see
setuid(2)). The
default is suid.
- log | delaylog | tmplog | nolog
- Control intent logging. File system integrity across system failure requires that logging be
enabled. The default is log.
- In log mode, file system structural changes are logged to disk before the system call returns
to the application. If the system crashes, fsck will complete logged operations that
have not yet completed.
- In delaylog mode, some system calls return before the intent log is written. This improves
the performance of the system, but some changes are not guaranteed until a short
time later when the intent log is written. This mode approximates traditional
UNIX system guarantees for correctness in case of system failures.
- In tmplog mode, the intent log is almost always delayed. This improves performance, but
recent changes may disappear if the system crashes. This mode is only
recommended for temporary file systems.
- In nolog mode, the intent log is disabled. The other three logging modes provide fast file
system recovery; nolog does not provide fast file system recovery. With nolog
mode, a full structural check must be performed after a crash; this may result in
loss of substantial portions of the file system, depending upon activity at the time
of the crash. Usually, a nolog file system should be rebuilt with mkfs after a
crash. The nolog mode should only be used for memory resident or very
temporary file systems.
- NOTE: nolog is available with the VxFS Advanced feature set only.
- blkclear
- Ensure that all data extents are cleared before being allocated to a file (requires
synchronous zeroing of certain newly allocated extents). This prevents
uninitialized data from appearing in a file being written at the time of a system
crash.
- remount
- Change the mount options for a mounted file system. In particular, remount can change
the logging and caching policies. It can also change a file system from read-only
to read/write.
- remount cannot change a file system from read/write to read-only, nor can it set the
snapof or snapsize attributes.
- snapof=filesystem
- Mount 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 special file containing a
mounted vxfs file system.
- NOTE: snapof=filesystem is available with the VxFS Advanced feature set only.
- snapsize=size
- Used in conjunction with snapof. size is the size in sectors of the snapshot file system being
mounted. This option is required only when the device driver is incapable of
determining the size of snapof_special, and will default to the entire device if not
specified.
- NOTE: snapsize=size is available with the VxFS Advanced feature set only.
- mincache=direct | dsync | unbuffered | closesync | tmpcache
- This option is used to alter the caching behavior of the file system.
- The direct value will cause any reads without the
O_SYNC flag, or any writes without the
O_SYNC flag, VX_DSYNC,
VX_DIRECT, and VX_UNBUFFERED caching
advisories, to be handled as if the VX_DIRECT caching
advisory had been set.
- The unbuffered value will cause any reads without the
O_SYNC flag, or any writes without the
O_SYNC flag, VX_DSYNC,
VX_DIRECT, and VX_UNBUFFERED caching
advisories, to be handled as if the VX_UNBUFFERED caching
advisory had been set.
- The dsync value will cause any writes without
the O_SYNC flag, or one of the VX_DIRECT,
VX_DSYNC, and VX_UNBUFFERED caching
advisories, to be handled as if the VX_DSYNC caching
advisory had been set.
- For the closesync, dsync,
unbuffered, and
direct values, when a file is closed, an equivalent of an
fsync(2) call will
be performed.
- The tmpcache value disables delayed extending writes,
trading off integrity for performance. When tmpcache is
chosen, vxfs does not zero out new extents allocated as
files are sequentially written. Uninitialized data may appear in files
being written at the time of a system crash.
See vxfsio(7)
for an explanation of VX_DIRECT, VX_DSYNC,
and VX_UNBUFFERED..
- NOTE: mincache=direct,
mincache=dsync,
mincache=tmpcache, and
mincache=unbuffered are available
with the VxFS Advanced feature set only.
- convosync=direct
| dsync | unbuffered |
closesync | delay
- This option is used to alter the caching behavior of the file system
for O_SYNC I/O operations.
- The direct value will cause any reads or writes with the O_SYNC flag to be handled as if
the VX_DIRECT caching advisory had been set.
- The dsync value will cause any writes with the O_SYNC flag to be handled as if the
VX_DSYNC caching advisory had been set.
- The unbuffered value will cause any reads or writes
with the O_SYNC flag to be handled as if
the VX_UNBUFFERED caching advisory had been set.
- The closesync value causes O_SYNC
writes to be delayed rather than to take effect immediately.
- The closesync, dsync,
unbuffered, and
direct values all cause the equivalent of an
fsync(2)
to be run when any file accessed with the
O_SYNC flag is closed.
- The delay value causes O_SYNC writes to be delayed rather than to take effect
immediately. Choosing this option causes vxfs to change all O_SYNC writes into
delayed writes. No special action is performed when closing a file. This option
effectively cancels any data integrity guarantees normally provided by opening a
file with O_SYNC.
- NOTE: The convosync option is available with the VxFS Advanced feature set only.
- datainlog | nodatainlog
- Normally, the vxfs file system will do O_SYNC writes by logging the data and the time
change to the inode (datainlog). If the nodatainlog option is used, the logging of
synchronous writes is disabled; O_SYNC writes will write the data into the file
and update the inode synchronously before returning to the user.
- NOTE: datainlog is available with the VxFS Advanced feature set only.
- largefiles | nolargefiles
- If nolargefiles is specified and the mount
succeeds, then the file system does not contain any files 2 gigabytes
or larger, and such files cannot be created. If
largefiles is specified and the mount succeeds, then
the file system may contain files 2 gigabytes or larger, and large
files can be created. For a mount to succeed, the option specifed here
must match the largefile compatibility flag (specified
previously by mkfs
(see mkfs_vxfs(1M))
or
fsadm
(see fsadm_vxfs(1M)).
- NOTE: Be careful when implementing large file system capability. System administration
utilities such as backup may experience problems if they are not large file aware.
- quota
- Enable disk quotas.
Notices
Only a privileged user can mount file systems.
Unlike some file system commands, multiple -o options to the mount command do not accumulate; the last option is used instead.
Files
- /etc/mnttab
- Table of mounted file systems.
References
fsadm_vxfs(1M),
fstyp(1M),
mkfs_vxfs(1M),
mount(1M),
setmnt(1M),
fsync(2),
setuid(2),
fs_vxfs(4),
mnttab(4),
vxfsio(7)
© 1997 The Santa Cruz Operation, Inc. All rights reserved.