mount Command
Purpose
Makes a file system available for use.
Syntax
mount [ -f ] [ -n node ] [ -o options ] [ -p ] [ -r ] [ -v vfsname ] [ -F AltFSfile ] [ -t type | [ device | node:directory ] directory | all | -a ] [-V [generic_options] special_mount_points ]
Description
The mount command instructs the operating system to make a file system available for use at a specified location (the mount point). In addition, you can use the mount command to build other file trees that are made up of directory and file mounts. The mount command mounts a file system that is expressed as a device by using the device or node:directory parameter on the directory that is specified by the directory parameter. After the execution of mount finishes, the directory that is specified becomes the root directory of the newly mounted file system.
Only users with root authority or users who are members of the system group with write access to the mount point can perform file or directory mounts. The file or directory might be a symbolic link. The mount command uses the real user ID, not the effective user ID, to determine whether the user has appropriate access. System group members can issue device mounts, provided they have write access to the mount point and to those mounts that are specified in the /etc/filesystems file. Users with root user authority can issue any mount command.
Users can mount a device provided they belong to the system group and have appropriate access. When mounting a device, the mount command uses the device parameter as the name of the block device and the directory parameter as the directory on which to mount the file system.
- The node (if the mount is remote).
- The object that is mounted.
- The mount point.
- The virtual-file-system type.
- The time mounted.
- Any mount options.
If you specify only the directory or node:directory parameter, the mount command takes it to be the name of the directory or file on which a file system, directory, or file is mounted (as defined in the /etc/filesystems file). The mount command looks up the associated device, directory, or file and mounts it. It is convenient to use the mount command because it does not require you to remember what is normally mounted on a directory or file. You can also specify only the device. In this case, the command obtains the mount point from the /etc/filesystems file.
The /etc/filesystems file must include a stanza for each mountable file system, directory, or file. This stanza must specify at least the name of the file system and either the device on which it resides or the directory name. If the stanza includes a mount attribute, the mount command uses the associated values. It recognizes five values for the mount attributes: automatic, true, false, removable, and readonly.
The mount all command causes all file systems with the mount=true attribute to be mounted in their normal places. This command is typically used during system initialization, and the corresponding mount operations are referred to as automatic mount operations.
By default, the mount command runs the wlmcntrl command to refresh the current assignment rules in the kernel after mounting the file system. In some situations (such as when many file systems are mounted at once, or when a rule for an inaccessible remote mount is present in the workload manager configuration), calling wlmcntrl automatically after mount might be undesirable.
If you want to override this behavior, set the environment variable
MOUNT_WLMCNTRL_SELFMANAGE to any value. Setting the environment variable
MOUNT_WLMCNTRL_SELFMANAGE to any value avoids calling the
wlmcntrl command during the mount operation. To refresh the current assignment
rules in the kernel, you must manually run wlmcntrl -u -d ""
command. For more
information, see wlmcntrl command.
- If the cdromd CD and DVD automount daemon is enabled, those devices are automatically mounted as specified in the /etc/cdromd.conf file. Use the cdumount or cdeject command to unmount an automatically mounted CD or DVD. Use stopsrc -s cdromd to disable the CD/DVD automount daemon.
- For CacheFS, the remote file system that is to be cached locally must be exported such that the
root ID of the local system is not remapped on the remote host to
nobody
(or the ID that the remote host uses as the anonymous user). For example, if host A has to export a file system /F that is mounted with CacheFS on host B then the /etc/exports on host A need to have an entry similar to:
depending on the mount options used for the local CacheFS mount./F -rw,root=B or /F -ro,root=B
- Mounting a JFS file system on a read-only logical volume is not supported.
- Using mount on a JFS2 File System
-
The mount command can also be used to access a snapshot of a JFS2 file system as a directory tree. The snapshot on device is mounted read-only at directory. A snapshot can be mounted only once. When mounting a JFS2 file system with snapshots, the snapshots are activated.
You can use the System Management Interface Tool (SMIT)
smit mount
fast path to run this command.Note: If the mount command encounters a Journaled File System (JFS) or Enhanced Journaled File System (JFS2) which was not unmounted before reboot, a replay of any JFS or JFS2 log records is attempted. To move a compatible JFS file system to a system that runs an earlier release of the operating system, the file system must always be unmounted cleanly before its movement. Failure to unmount first might result in an incompatible JFS log device. If the movement results in an unknown log device, the file system must be returned to the system that runs the latter operating system release, and fsck must be run on the file system.
Flags
Item | Description |
---|---|
-a | Mounts all file systems in the /etc/filesystems file with stanzas that contain the true mount attribute. |
all | Same as the -a flag. |
-f | Requests a forced mount during system initialization to enable mounting over the root file system. |
-F AltFSfile | Mounts on a file of an alternate file system, other than the /etc/filesystems file. |
-n node | Specifies the remote node that holds the directory to be mounted. The node can be specified
as a colon-separated IPv6 address. If the node is specified with the node:directory
format, the colon-separated IPv6 address must be enclosed in square brackets. |
-p | Mounts a file system as a removable file system. While open files are on it, a removable mounted file system behaves the same as a normally mounted file system. However, when no files are open (and no process has a current directory on the file system), all of the file system disk buffers in the file system are written to the medium, and the operating system forgets the structure of the file system. |
-r | Mounts a file system as a read-only file system, regardless of its previous specification in the /etc/filesystems file or any previous command-line options. |
-t type | Mounts all stanzas in the /etc/filesystems file that contain the type=type attribute and are not mounted. The type parameter specifies the name of the group. |
-v vfsname | Specifies that the file system is defined by the vfsname parameter in the /etc/vfs file. |
- File System Specific Options
-
Item Description -o options Specifies options. Options that are entered on the command line must be separated only by a comma. The following file system-specific options do not apply to all virtual file system types: - atime
- Turns on access-time updates. If neither atime nor noatime option is specified, then atime option is the default value.
- bsy
- This option prevents the mount operation if the directory to be mounted over is the current working directory of a process.
- cio
- Specifies the file system to be mounted for concurrent readers and writers. I/O on files in this
file system behaves as if they are opened with O_CIO specified in the
open() system call. Using the cio option prevents access
in any manner other than CIO. It is impossible to use cached I/O on a file system mounted with the
cio option. Mapping commands such as mmap() and
shmat() fails with EINVAL when used on any file in a file system mounted with the
cio option. One side-effect of this is that it is impossible to run binaries
out of a cio mounted file system, since the loader might use
mmap(). Note: When you mount the file system by using the cio option, all applications must manage the serialization of files. Quotas are not supported by the cio option because quotas have their own serialization code.
- dev
- Specifies that you can open devices from this mount. If neither dev nor nodev option is specified, then dev option is the default value.
- dio
- Specifies that I/O on the file system behaves as if all the files were opened with
O_DIRECT specified in the open() system call. Note: Using the -odio or -ocio flags can help performance on certain workloads, but users must be aware that using these flags prevents file caching for these file systems. Because readahead is disabled for these file systems, it might decrease performance for large sequential reads.
- fmode=octal
- Specifies the mode for a file and directory. The default is 755.
- gid=gid
- Specifies the GID that is assigned to files in the mount. The default is bin.
- log=lvname
- Specifies the full path name of the file system logging logical volume name where the following file-system operations are logged.
- log=NULL
-
Turns off logging and flushing of metadata for JFS2 file systems. Metadata is not flushed to the disk until the file system is unmounted. If the system stops abnormally before the file system is unmounted, the metadata changes are lost.
The JFS2 file system depends on the log information for metadata consistency. If the system stops abnormally during the metadata flush process for the JFS2 file system when the unmount operation is in progress, the file system cannot be recovered to a consistent state upon system reboot. In this case, the file system must be re-created.
Attention: Because of the risk of data loss, use this flag with caution.
- maxpout=value
- Specifies the pageout level for files on this file system at which threads must be slept. If maxpout option is specified, the minpout option must also be specified. Value must be nonnegative and greater than minpout. The default is the kernel maxpout level.
- minpout=value
- Specifies the pageout level for files on this file system at which threads must be readied. If minpout is specified, the maxpout must also be specified. Value must be nonnegative. The default is the kernel minpout level.
- nBufferPerPagerDevice=value
-
Specifies the number of buffers for JFS2 file system on a per-file system basis. The nBufferPerPagerDevice mount option specifies only the number of file system buffers that start on the paging device. If the nBufferPerPagerDevice mount option is not specified, then the value of the j2_nBufferPerPagerDevice tunable parameter is used to allocate the file system buffers. The range for nBufferPerPagerDevice mount option is identical to that of the j2_nBufferPerPagerDevice tunable parameter.
The j2_dynamicBufferPreallocation tunable parameter of the ioo command must be tuned to specify the file system buffers for JFS2 file system on a per-system basis. In a server with many file systems, a system might run out of buffers if a file system has a larger number of concurrent I/O than the other file systems. Currently, increasing the value of the j2_nBufferPerPagerDevice tunable parameter applies to all the file systems. If you set the j2_nBufferPerPagerDevice tunable parameter to a large value, a high amount of pinned memory is used when only one file system requires a higher buffer value than the rest. In such cases, you can use the nBufferPerPagerDevice mount option to specify the file system buffers for JFS2 file system on a per-file system basis.
After tuning the j2_dynamicBufferPreallocation tuning parameter of the ioo command, run the vmstat -v command. In the output displayed after running the vmstat -v command, check the
number of external pager filesystem I/Os blocked with no fsbuf
counter. If the value of this counter increases quickly and keeps increasing, then the nBufferPerPagerDevice mount option can be used to specify the number of file system buffers for JFS2 on a per-file system basis. If the kernel must wait for free buffers, it puts the process on a wait list before the I/O operation starts and wakes up the process when buffers are available. If you are using striped logical volumes or disk arrays, consider increasing the number of buffers for JFS2 file system.
- noatime
- Turns off access-time updates. Using this option can improve performance on file systems where many files are read frequently and seldom updated. If you use the option, the last access time for a file cannot be determined. If neither atime nor noatime option is specified, then atime option is the default value.
- nocase
- Turns-off case mapping. This option is useful for CDROMs that uses the
ISO 9660:1998/HSG
standard.
- nodev
- Specifies that you cannot open devices from this mount. This option returns a value of ENXIO if a failure occurs. If neither dev nor nodev option is specified, then dev option is the default value.
- noguard
- Mount the file system regardless of the current
mountguard
setting that would otherwise guard the file system against unsupported concurrent mounts in a PowerHA® or other clustering environment. Ifmountguard
is enabled by the chfs or crfs command, the file system cannot be mounted if it appears to be mounted on another node or system. Specifying the noguard option temporarily overrides themountguard
setting.
- norbr
- Mounts the file system without the release-behind-when-reading capability. If none of the release-behind options are specified, the norbrw is the default value.
- norbrw
- Mounts the file system without both the release-behind-when-reading and release-behind-when-writing capabilities. If none of the release-behind options are specified, the norbrw is the default value.
- norbw
- Mounts the file system without the release-behind-when-writing capability. If none of the release-behind options are specified, the norbrw is the default value.
- nosuid
- Specifies that execution of setuid and setgid programs by way of this mount is not allowed. This option returns a value of EPERM if a failure occurs. If neither suid nor nosuid option is specified, then suid option is the default value.
- rbr
- Mount the file system with the release-behind-when-reading capability. When sequential reading
of a file in this file system is detected, the real memory pages that are used by the file are
released once the pages are copied to internal buffers. If none of the release-behind options are
specified, the norbrw is the default. Note: When rbr is specified, the D_RB_READ flag is ultimately set in the _devflags field in the pdtentry structure.
- rbw
- Mount the file system with the release-behind-when-writing capability. When sequential writing
of a file in this file system is detected, the real memory pages that are used by the file are
released once the pages written to disk. If none of the release-behind options are specified, the
norbrw is the default. Note: When rbw is specified, the D_RB_WRITE flag is set.
- rbrw
- Mount the file system with both release-behind-when-reading and release-behind-when-writing
capabilities. If none of the release-behind options are specified, the norbrw
is the default. Note: If rbrw is specified, both the D_RB_READ and the D_RB_WRITE flags are set.
- remount
- Changes the mount options of a mounted file system. For
JFS2 file systems, you can specify the following mount options with the remount option to change the
settings of a mounted file system. For any mount options not specified, no change is made to the
current corresponding settings of the file system.
atime, noatime; dev, nodev; logdev; maxpout, minpout; rbr, norbr; rbw, norbw; rbrw, norbrw, rw, ro, rox; suid, nosuid.
Note:- External-snapshot mounted file systems cannot be remounted to read/write file systems.
- You cannot use the rw and ro remount options on a file system that is managed by a data management application programming interface (DMAPI).
- If logdev is specified, the new log device must be in the same volume group as the existing log device. You cannot change an external log device to an internal log device or vice-versa if you specify the logdev option. Use the logshuffle option in the chfs command for that functionality.
For NFS, there are three types of mount requests.duplicate mount
- If the node, object, mount point, and the options that are specified in the mount command are the same as those for an existing mount, the mount command returns information about a successful mount, but a new mount is not created.
new mount
- If the remount option is not specified, the mount command creates a new mount. If the node, object, mount point, or the constant options that are specified in the mount command are different than those for the existing mounts, the mount command fails if the remount option is specified.
remount
- If the node, object, and mount point are the same as those for a top-most mount, but the
remount options are different, the remount operation modifies the mount options of an existing
mount. In this case, NFS performs the remount operation.
A top-most mount does not have another mount on top of it. For remount requests, the following options can be modified: acdirmax, acdirmin, acregmax, acregmin, actimeo, fastattr, grpid, hard, intr, noac, nocto, nodev, nointr, nosuid, posix, retrans, ro, rsize, rw, secure, sec, soft, timeo, wsize, biods, extraattr, nodircache, prefer, otwattr, maxgroups, and proto. Other options are classified as constant options.
- ro
- Specifies that the mounted file is read-only, regardless of its previous option specification in the /etc/filesystems file or any previous command-line options. The default value is rw.
- rw
- Specifies that the mounted file is read/write accessible, regardless of its previous option specification in the /etc/filesystems file or any previous command-line options. The default value is rw.
- snapshot
- Specifies the device to be mounted is a snapshot. The snapped file system for the specified snapshot must already be mounted or an error message is displayed.
- snapto=snapshot
- Specifies the location to start a snapshot with the value of snapshot when
mounting the specified JFS2 file system. The snapshot parameter specifies the
name of an internal snapshot if the snapshot parameter does not included a
forward slash (
/
), that is, no path information.
- suid
- Specifies that execution of setuid and setgid programs by way of this mount is allowed. If neither suid nor nosuid option is specified, then suid option is the default value.
- upcase
- Changes case mapping from default lowercase to uppercase. This option is useful for CDROMs that
uses the
ISO 9660:1998/HSG
standard.
- uid=uid
- Specifies the UID that is assigned to files in the mount, the default is bin.
- wrkgrp=workgroup
- Specifies the workgroup that the SMB server belongs.
- NFS Specific Options
-
Item Description -o options Specifies options. Options that you enter on the command line must be separated only by a comma without any space. The following NFS-specific options do not apply to all virtual file system types: - acdirmax=n
- Holds cached attributes for no more than n seconds after directory update. The default is 60 seconds.
- acdirmin=n
- Holds cached attributes for at least n seconds after directory update. The default is 30 seconds.
- acl
- Requests by using the Access Control List RPC program for this NFS mount. If the acl option is used, the ACL RPC program is used only if the NFS server provides it. The default is noacl.
- acregmax=n
- Holds cached attributes for no longer that n seconds after file modification. The default is 60 seconds.
- acregmin=n
- Holds cached attributes for at least n seconds after file modification. The default is 30 seconds.
- actimeo=n
- Sets minimum and maximum times for regular files and directories to n seconds. If this option is set, it overrides any settings for the acregmin, acregmax, acdirmin, and acdirmax options.
- bg
- Attempts mount in the background if first attempt is unsuccessful. The default value is fg.
- biods=n
- Sets the maximum number of biod threads that perform asynchronous I/O RPC
requests for an NFS mount. The maximum value that can be set is
128
. Values greater than 128 are limited to 128 within the NFS client. The NFS client dynamically manages the number of running biod threads up to the maximum based on activity. The default maximums for the different NFS protocols are7
for NFS version 2 and32
for NFS version 3 and NFS version 4. These defaults are subject to change in future releases.
- cio
- Specifies the file system to be mounted for concurrent readers and writers. I/O on files in this
file system behaves as if they were opened with O_CIO specified in the
open() system call. Using this option prevents access in any manner other than
CIO. It is impossible to use cached I/O on a file system mounted with the cio
option. Mapping commands such as mmap() and shmat() fails with
EINVAL when used on any file in a file system mounted with the cio option. One
side-effect of this is that it is impossible to run binaries out of a cio
mounted file system, since the loader might use mmap().Note: When you mount the file system by using the cio option, all applications must manage the serialization of files. Quotas are not supported by the cio option because quotas have their own serialization code.
- cior
- Specifies to allow read-only files to open in the file system. I/O on files in this file system behaves as if they were opened with O_CIO | O_CIOR specified in the open() system call. Using this option prevents access in any manner other than O_CIO | O_CIOR and read-only. An attempt to open only with O_CIO also fails. This option can be used only along with cio.
- dio
- Specifies that I/O on the file system behaves as if all the files were opened with
O_DIRECT specified in the open() system call. Note: Using the -odio or -ocio flags can help performance on certain workloads, but users must be aware that using these flags prevents file caching for these file systems. Because readahead is disabled for these file systems, it might decrease performance for large sequential reads.
- fastattr
- This option bypasses the requirement that a file, which is currently written be sent to the server before the attributes of the file are read. This option is to be used with caution, since it causes the client to assume that the file data that has not yet reached the server is written without problem. If there are write errors, the client and server have different opinions on what the size of the file really is. Likewise, a client is not aware of attribute changes to the file that are made by another client, so this option must not be used in environments where two clients are writing to the same files.
- fg
- Attempts mount in foreground if first attempt is unsuccessful. fg is the default value.
- grpid
- Directs any file or directory that is created on the file system to inherit the group ID of the parent directory.
- hard
- Retries a request until the server responds. The option is the default value.
- intr
- This option allows keyboard interrupts on hard mounts.
- llock
- Requests that files lock locally at the NFS client. NFS network file locking requests are not sent to the NFS server if the llock option is used.
- maxgroups=n
- This option indicates that NFS RPC calls by using AUTH_UNIX might include
up to n member groups of information. Using this option to increase the number of
member groups beyond the RPC protocol standard of 16 only works against servers that support more
than 16 member groups. Otherwise, the client experiences errors.
Values less than 16 or greater than 64 are ignored. By default, the protocol standard maximum of 16 is adhered to. AIX® NFS servers accept and process AUTH_UNIX credentials with up to 64 groups that start with AIX 5L Version 5.2 with the 5200-01 Recommended Maintenance package. The actual number of member groups that are sent by the NFS client depends on the number of groups the involved user is a member of, and might be limited by the length of the NFS client's hostname (which is included in the AUTH_UNIX information).
- noac
- Specifies that the mount command performs no attribute or directory caching. If you do not specify this option, the attributes (including permissions, size, and timestamps) for files and directories are cached to reduce the need to perform over-the-wire NFSPROC_GETATTR Remote Procedure Calls (RPCs). The NFSPROC_GETATTR RPC enables a client to prompt the server for file and directory attributes. The acregmin, acregmax, acdirmin, and acdirmax options control the length of time for which the cached values are retained.
- noacl
- Specifies not to use the Access Control List RPC program for this NFS mount request. The default is noacl.
- nointr
- Specifies no keyboard interrupts allowed on hard mounts.
- port=n
- Sets server Internet Protocol (IP) port number to n. The default value is the 2049.
- posix
- Requests that
pathconf
information is exchanged and made available on an NFS Version 2 mount. Requires a mount Version 2 rpc.mountd at the NFS server.
- proto=[udp|tcp]
- Specifies the transport protocol. The default is tcp. Use the
proto=[udp|tcp] option to override the default.
proto=udp cannot be specified if vers=4.
- retrans=n
- Sets the number of NFS transmissions to n. The default value is 5. The retrans setting determines how many times the NFS client retransmits a given UDP RPC request to an NFS server for file system operations. The retrans setting is not used during communication with the NFS server rpc.mountd service when processing NFS version 2 and 3 mounts. Retries to rpc.mountd are controlled with the retry mount option.
- retry=n
- Sets the number of times the mount is attempted to n; the default value is 1000. When the retry value is 0, the system makes 10,000 attempts.
- rsize=n
- Sets the read buffer size to n bytes. Beginning with AIX Version 6.1, the default value is 64 KB and the maximum value is 512 KB when using Version 3 and Version 4 of the NFS protocol.
- secure
- Specifies that the mount command uses Data Encryption Standard (DES) for NFS transactions. The Data Encryption Standard (DES) is not supported in NFS Version 4, use krb5 instead.
- sec=flavor[:flavor...]
- Specifies a list of security methods that might be used to access files under the mount point.
Allowable flavor values are:
- sys
- UNIX® authentication. This value is the default method.
- dh
- DES authentication. The Data Encryption Standard (DES) is not supported in NFS Version 4, use krb5 instead.
- krb5
- Kerberos. Authentication only.
- krb5i
- Kerberos. Authentication and integrity.
- krb5p
- Kerberos. Authentication, integrity, and privacy.
The secure option might be specified, but not along with a sec option. The secure option is deprecated and might be eliminated in a future release. Use sec=dh instead.
- sec=[flavor1:...:flavorn]
- The sec option specifies the security flavor list for the NFS mount. The available flavors are des, unix, sys, krb5, krb5i, and krb5p. This option applies to AIX 5.3 or later.
- shortdev
- Specifies that you are mounting a file system from a host that does not support 32-bit device special files.
- soft
- This option returns an error if the server does not respond. The default value is hard.
- timeo=n
- Sets the Network File System (NFS) time out period to n tenths of a second. For TCP mounts, the default timeout is 100, which equals 10 seconds. For UDP mounts, the default timeout is 11, which equals 1.1 seconds, but varies depending on the NFS operation that takes place. For UDP mounts, the timeout increases for each failed transmission, with a maximum value of 20 seconds. Each transmission will be attempted twice after which the timeout value is updated. The timeo option does not apply to communication from the NFS client to the rpc.mountd service on NFS servers. A timeout of 30 seconds is used when making calls to rpc.mountd.
- vers=[2|3|4]
- Specifies NFS version. The default is the version of the NFS protocol that is used between the client and server and is the highest one available on both systems. If the NFS server does not support NFS Version 3, the NFS mount uses NFS Version 2. Use the vers=[2|3|4] option to select the NFS version. By default, the NFS mount never uses NFS Version 4 unless specified. The vers=4 applies to AIX 5.3 or later.
- wsize=n
- Sets the write buffer size to n bytes. Beginning with AIX Version 6.1, the default value is 64 KB and the maximum value is 512 KB when using Version 3 and Version 4 of the NFS protocol.
- CacheFS Specific Options
-
The CacheFS-specific version of the mount command mounts a cached file system; if necessary, it NFS-mounts its back file system. It also provides several CacheFS-specific options for controlling the caching process.
To mount a CacheFS file system, use the mount command with the -V flag followed by the argument. The following mount flags are available.
The following arguments to the -o flag are specifically for CacheFS mounts. Options that you enter on the command line must be separated only by a comma without any space.Note: The backfstype argument must be specified.Item Description -o Specifies options. - acdirmax=n
- Specifies that cached attributes are held for no more than n seconds after a directory update. Before n seconds, CacheFS checks to see whether the directory modification time on the back file system changes. If the directory modification time on the back file system changes, all information about the directory is purged from the cache and new data is retrieved from the back file system. The default value is 60 seconds.
- acdirmin=n
- Specifies that cached attributes are held for at least n seconds after directory update. After n seconds, CacheFS checks to see whether the directory modification time on the back file system changes. If the directory modification time on the back file system changes, all information about the directory is purged from the cache and new data is retrieved from the back file system. The default value is 30 seconds.
- acregmax=n
- Specifies that cached attributes are held for no more than n seconds after file modification. After n seconds, all file information is purged from the cache. The default value is 30 seconds.
- acregmin=n
- Specifies that cached attributes are held for at least n seconds after file modification. After n seconds, CacheFS checks to see whether the file modification time on the back file system changes. If the file modification time on the back file system changes, all the information about the file is purged from the cache and new data is retrieved from the back file system. The default value is 30 seconds.
- actimeo=n
- Sets acregmin, acregmax, acdirmin, and acdirmax to n.
- backfstype=file_system_type
- The file system type of the back file system (for example, nfs).
- backpath=path
- Specifies where the back file system is already mounted. If this argument is not supplied, CacheFS determines a mount point for the back file system.
- cachedir=directory
- The name of the cache directory.
- cacheid=ID
- ID is a string that specifies an instance of a cache. If you do not specify a cache ID, CacheFS constructs one.
- demandconst
- Enables maximum cache consistency checking. By default, periodic consistency checking is
enabled. When you enable demandconst, it checks on every read and write. Note: If this option is used the first time a specific CacheFS is mounted, then this option must also be specified for subsequent mounts. There is state information that is stored in the cache control files that enforces consistent use of this option.
- local_access
- This option causes the front file system to interpret the mode bits used for access checking instead or having the back file system verify access permissions. Do not use this argument with secure NFS.
- noconst
- Disables cache consistency checking. By default, periodic consistency checking is enabled.
Specify noconst only when you know that the back file system is not modified.
Trying to perform cache consistency check by using cfsadmin-s results in error.
demandconst and noconst are mutually exclusive. Note: If this option is used the first time a specific CacheFS is mounted, then the option must also be specified for subsequent mounts. There is state information that is stored in the cache control files that enforces consistent use of this option.
- purge
- Purges any cached information for the specified file system. Note: If this option is used the first time a specific CacheFS is mounted, then the option must also be specified for subsequent mounts. There is state information that is stored in the cache control files that enforces consistent use of this option.
- rw | ro
Read-write
(default) orread-only
.
- suid | nosuid
- Allows (default) or disallows set-uid execution.
- write-around | non-shared
- Writes modes for CacheFS. The write-around mode (the default) handles the
writes the same as NFS does. Writes are made to the back file system, and the affected file is
purged from the cache. You can use the non-shared mode when you are sure that
no one else is writing to the cached file system. Note: If this option is used the first time a specific CacheFS is mounted, then the option must also be specified for subsequent mounts. There is state information that is stored in the cache control files that enforces consistent use of this option.
- mfsid
- Turns on global view. In the NFS v4 system, you can traverse through the exported namespace on the server side. You need to specify this option to go over the file system.
Restriction: mfsid is an option if the backend file system for CacheFS is NFS v4.-V Mounts a CacheFS file system. - Server Message Block (SMB) client file system specific options
-
Item Description -o options Specifies options for mounting the SMB client file system. Options that you enter on the command line must be separated only by a comma. Do not insert a space before or after a comma. The following options are available for the SMB client file system: - fmode
- Sets a file or directory to octal mode for access permissions. The default value is 755.
- uid
- Assigns a user ID to files during the mount operation. The default value is
root
. - gid
- Assigns a group ID to files during the mount operation. The default value is
system
. - wrkgrp
- Specifies the workgroup to which the SMB server belongs. This parameter is mandatory to mount the SMB client file system.
- port
- Specifies the port number. The valid values are 445 and 139. The default value is 445. Port 139
is supported only when the specified server address is in IPv4
format.Note: encryption option is not supported when the port specified is 139.
- pver
- Specifies the version of the SMB protocol that is used to communicate with the SMB server. The
valid values are
2.1,3.0.2
andauto
. For the valueauto
, the SMB protocol version2.1
or version3.0.2
is used based on the specified SMB server. - signing
- Specifies whether the file system in the SMB client needs a digital signature for communication
with the SMB server file system. The valid values are
enabled
andrequired
. When this parameter is set toenabled
, the file system in the SMB client does not digitally sign the data packets unless the file system in the SMB server needs digital signatures for communication with the file system in the SMB server. When this parameter is set torequired
, the file system in the SMB client must digitally sign the data packets for communication with the file system in the SMB server. If you do not specify the value for the signing parameter by using the mount command, a default value is used from the tunable parameter values of the kernel that are set by using the smbctune command. - secure_negotiate
- Specifies whether the file system in the SMB client needs a secure dialect negotiation
capability. SMB Dialect 3.0.2 implements secure dialect negotiation to protect against
security-downgrade attacks. The valid values are
desired
,required
, anddisabled
. If you do not specify the value by using the mount command, a default value is used from tunable parameter values of the kernel that are set by using the smbctune command. - encryption
- Specifies whether the file system in the SMB client requires data encryption. The valid values
are
desired
,required
, anddisabled
. If you do not specify the value by using the mount command, a default value is used from the tunable parameter values of the kernel that are set by using the smbctune command.Note:encryption
option is not supported when the port specified is 139.
-o options (continued) - spn
- Specifies the service principal name (SPN) that must be used in the SMB client mount points. The format of the spn parameter is cifs/<smbServerHostName>, where smbServerHostName is the fully qualified domain name (FQDN) of the SMB server or the name that the Kerberos resolves as the SMB server. By default, SPN is constructed automatically by the SMB client file system as cifs/<smbServerHostName>.
If the options that are used with the mount command (
pver, signing, secure_negotiate, or encryption
) are unspecified by using the -o flag, the default values for the mount command options are initialized by using the new values of the kernel tunable parameters (smbc_protocol_version, smbc_signing, smbc_secure_negotiate, smbc_encryption
). The kernel tunable parameters are initialized from tunable parameters that are defined in the smbctune.conf file. These parameters can also be modified by using the smbctune command.The following table shows the kernel tunable parameters of the mount command and the corresponding kernel tunable parameters that can be set in the smbctune.conf file:Options of the -o flag (mount command) Corresponding kernel tunable parameter of the smbctune.con file Valid values pver smbc_protocol_version 2.1, 3.0.2, auto
signing smbc_signing enabled, required
secure_negotiate smbc_secure_negotiate desired, required, disabled
encryption smbc_encryption desired, required, disabled
Security
Examples
-
To list the mounted file systems, enter the following command:
This command produces output similar to the following output:mount
node mounted mounted over vfs date options ---- ------- ------------ --- ------------ ------------------- /dev/hd0 / jfs Dec 17 08:04 rw, log =/dev/hd8 /dev/hd3 /tmp jfs Dec 17 08:04 rw, log =/dev/hd8 /dev/hd1 /home jfs Dec 17 08:06 rw, log =/dev/hd8 /dev/hd2 /usr jfs Dec 17 08:06 rw, log =/dev/hd8 sue /home/local/src /usr/code nfs Dec 17 08:06 ro, log =/dev/hd8
For each file system, the mount command lists the node name, the device name, the name under which it is mounted, the virtual-file-system type, the date and time it was mounted, and its options.
-
To mount all default file systems, enter the following command:
mount all
This command sequence mounts all standard file systems in the /etc/filesystems file that is marked by the mount=true attribute.
-
To mount a remote directory, enter the following command:
mount -n nodeA /home/tom.remote /home/tom.local
This command sequence mounts the /home/tom.remote directory that is located on
nodeA
onto the local /home/tom.remote directory. It assumes the default VfsName parameter=remote, which must be defined in the /etc/vfs file. -
To mount a file or directory from the /etc/filesystems file with a specific type, enter the following command:
mount -t remote
This command sequence mounts all files or directories in the /etc/filesystems file that have a stanza that contains the type=remote attribute.
-
To CacheFS-mount the file system that is already NFS-mounted on /usr/abc, enter the following command:
mount -V cachefs -o backfstype=nfs,backpath=/usr/abc, cachedir=/cache1 server1:/user2 /xyz
The lines similar to the following appear in the /etc/mnttab file after the mount command is executed:server1:/user2 /usr/abc nfs /usr/abc /cache1/xyz cachefs backfstype=nfs
-
To mount a snapshot, enter the following command:
mount -o snapshot /dev/snapsb /home/janet/snapsb
This command mounts the snapshot that is contained on the /dev/snapsb device onto the /home/janet/snapsb directory.
-
To mount a file system and create a snapshot, enter the following command:
mount -o snapto=/dev/snapsb /dev/sb /home/janet/sb
This command mounts the file system that is contained on the /dev/sb device onto the /home/janet/sb directory and creates a snapshot for the file system on the /dev/snapsb device.
-
To access files on an SMB server as a local file system, enter the following command:
mount -v cifs -n pezman/user1/pass1 -o uid=201,fmode=750 /home /mnt
-
To mount an SMB client file system as a local mount point, enter the following command:
mount -v smbc -n llm140.xyz.com/cec102usr1/Passw0rd \ -o wrkgrp=SMB_21.FVT,port=445,signing=required /some_share /mnt
Where,
llm140.xyz.com
is the Windows™ server,cec102usr1
is the Kerberos user name,Passw0rd
is the password of the Kerberos user,SMB_21.FVT
is the workgroup,some_share
is the share point on the Windows system, and/mnt
is the local mount point. -
To remount the mounted read-only JFS2 file system to a read/write file system, enter the following command:
mount -o remount,rw fsname
-
To mount all on a file /tmp/fs1 of an alternate file system, enter the following command:
mount -F /tmp/fs1 all
Files
Item | Description |
---|---|
/etc/filesystems | Lists the known file systems and defines their characteristics. |
/etc/vfs | Contains descriptions of virtual-file-system types. |