Changes the options used to mount a directory from an NFS server.
/usr/sbin/chnfsmnt -f PathName -d RemoteDirectory -h RemoteHost [ -t { rw | ro } ] [ -m MountTypeName ] [ -w { fg | bg } ] [ -X | -x ] [ -S | -H ] [ -Y | -y ] [ -Z | -z ] [ -e | -E ] [ -a | -A ] [ -j | [ -J ] [ -q | [ -Q ] [ -g | [ -G ] [ -s | -n ] [ -I | -B | -N ] [ -r TimesToRetry ] [ -R NumRetrans ] [ -b ReadBufferSize ] [ -c WriteBufferSize ] [ -o TimeOut ] [ -P PortNumber ] [ -u AcRegMin ] [ -U AcRegMax ] [ -v AcDirMin ] [ -V AcDirMax ] [ -T AcTimeO ] [ -p NumBiods ] [ -K { any | 2 | 3 } ] [ -k { any | tcp | udp } ] [ -M security_methods ] [ -i { dio | cio [ ,cior ] } ]
The chnfsmnt command changes the mount options of a currently mounted file system. However, before you can change the attributes of a mount, the /etc/filesystems file must contain an entry for the file system. This command unmounts the directory, changes the specified options, and mounts the directory with the new options.
| Item | Description |
|---|---|
| -A | The /etc/filesystems entry for this file system will specify that it should be automatically mounted at system restart. |
| -a | The /etc/filesystems entry for this file system specifies that it should not be automatically mounted at system restart. This is the default. |
| -B | Modifies the entry in the /etc/filesystems file and remounts the file system using the flags and parameters specified. This flag is the default. |
| -b ReadBufferSize | Indicates the size of the read buffer in N bytes. |
| -c WriteBufferSize | Indicates the size of the write buffer in N bytes. |
| -d RemoteDirectory | Specifies the directory that will be mounted on the path name specified. |
| -E | Allows keyboard interrupts on hard mounts. |
| -e | Prevents keyboard interrupts on hard mounts. This flag is the default. |
| -f PathName | Specifies the mount point for the directory. |
| -G | Directs any file or directory created on the file system to inherit the group ID of the parent directory. |
| -g | Does not direct new files or directories created on the file system to inherit the group ID of the parent directory. This is the default. |
| -H | Makes the mount a hard mount, which causes the client to continue trying until the server responds. |
| -h RemoteHost | Specifies the NFS server that is exporting the directory. |
| -I | Changes the entry in the /etc/filesystems file but does not remount the directory. |
| -i | Specifies I/O mode for the mount. The options
are:
|
| -J | Indicates that acls are used on this mount. |
| -j | Indicates that acls are not used on this mount. This is the default. |
| -K | Specifies the NFS version used for this NFS mount. This flag
only applies to AIX® 4.2.1 or later. The options are:
|
| -k | Specifies the transport protocol used for the mount. The
options are:
|
| -M security_methods | A list of security methods to use when attempting the mount. A comma separated list of the values sys, dh, krb5, krb5i, krb5p, which correspond to UNIX, DES, Kerberos 5, Kerberos 5 with integrity, and Kerberos 5 with privacy. Multiple values are allowed, but are only meaningful with NFS version 4 mounts. If multiple methods are given for a version 2 or 3 protocol mount, the first method will be used. For a NFS version 4 mount, the methods will be tried in listed order. |
| -m MountTypeName | Corresponds to the type field in the stanza of the entry in the /etc/filesystems file. When the mount -t command MountTypeName is issued, all of the currently unmounted file systems with a field type equal to the string are mounted. |
| -N | Prevents modification of the corresponding entry in the /etc/filesystems file if it exists. If the directory is currently mounted, it is unmounted and then mounted again with the flags and parameters specified. |
| -n | Instructs the mount not to use a more secure protocol. This flag is the default. |
| -o TimeOut | Indicates the length of the NFS time out in N tenths of a second. |
| -P PortNumber | Indicates the IP port number for the server. |
| -p NumBiods | Specifies the number of biod daemons that are allowed to work on a particular file system. The default is 7 for NFS version 2 and 32 for NFS version 3 and NFS version 4. |
| -Q | Requests that no posix pathconf information be exchanged and made available on an NFS Version 2 mount. Requires a mount Version 2 rpc.mountd at the NFS server. |
| -q | Specifies that no posix pathconf information is exchanged if mounted as an NFS Version 2 mount. This is the default. |
| -r TimeToRetry | Indicates the number of times to retry a mount. The default is 1000. |
| -R NumRetrans | Specifies, for a soft mount, the number of times that a request is to be transmitted if it is not acknowledged by the server. If the request goes unacknowledged after NumRetrans transmissions, the client gives up on the request. If this flag is not specified, the default value of 3 is used. |
| -S | Makes the mount a soft mount, which means that the system returns an error if the server does not respond. |
| -s | Instructs the mount to use a more secure protocol. |
| -TAcTimeO | Sets minimum and maximum time allowed for regular files and directories to AcTimeO seconds. If this option is specified, the other cached attribute times are overridden. |
| -t | Specifies whether the directory will be mounted as read-write
or read-only.
|
| -U AcRegMax | Holds cached attributes for no more than AcRegMax seconds after file modification. |
| -u AcRegMin | Holds cached attributes for at least AcRegMin seconds after file modification. |
| -V AcDirMax | Holds cached attributes for no more than AcDirMax seconds after directory update. |
| -v AcDirMin | Holds cached attributes for at least AcDirMin seconds after directory update. |
| -w { fg | bg } | Indicates whether the mount should be attempted in the foreground (fg) or background (bg). If bg is specified and the attempt to mount the directory fails, the mount will be tried again in the background. The fg parameter is the default. |
| -X | Specifies that the server does support long device numbers. This is the default. |
| -x | Specifies that the server does not support long device numbers. |
| -Y | Indicates that the execution of suid and sgid programs are allowed in this file system. This is the default. |
| -y | Indicates that the execution of suid and sgid programs is not allowed in this file system. |
| -Z | Indicates that device access through this mount is allowed. This is the default. |
| -z | Indicates that device access through this mount is not allowed. |
To change a mount to read-only, enter:
chnfsmnt -f /usr/man -d /usr/man -h host1 -t roIn this example, the chnfsmnt command changes the attributes of the mounted directory to read-only.
| Item | Description |
|---|---|
| /etc/filesystems | Lists the remote file systems to be mounted during the system restart. |
Attention RBAC users and Trusted AIX users: This command can perform privileged operations. Only privileged users can run privileged operations. For more information about authorizations and privileges, see Privileged Command Database in Security. For a list of privileges and the authorizations associated with this command, see the lssecattr command or the getcmdattr subcommand.