mount_vxfs(ADM)

Synopsis

mount [-F vxfs] [generic_options] [-r] [-o specific_options] special mount_point

Description

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(ADM) are used to determine the file system type.

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This command executes faster if it is not required to autodetect file system types. If possible, specify -F vxfs

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-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(S)). 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.

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NOTE: nolog is available with the VxFS Advanced feature set only.

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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.

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NOTE: snapof=filesystem is available with the VxFS Advanced feature set only.

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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.

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NOTE: snapsize=size is available with the VxFS Advanced feature set only.

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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(S) 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(HW) for an explanation of VX_DIRECT, VX_DSYNC, and VX_UNBUFFERED..

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NOTE: mincache=direct, mincache=dsync, mincache=tmpcache, and mincache=unbuffered are available with the VxFS Advanced feature set only.

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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(S) 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.

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NOTE: The convosync option is available with the VxFS Advanced feature set only.

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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.

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NOTE: datainlog is available with the VxFS Advanced feature set only.

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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(ADM)) or fsadm (see fsadm_vxfs(ADM)).

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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.

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quota

Enable disk quotas.

Notices

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