chnfs Command

Purpose

Changes the configuration of the system to invoke a specified number of nfsd daemons or to change NFS global configuration values.

Syntax

chnfs [ -b NumberofBiod ] [ -n NumberOfNfsd ] [ -l NumberOfLockd ] [ -I | -B | -N ] [ -s | -S ] [ -v | -V ] [ -r v4_root_node ] [ -p v4_public_node ] [ -L v4_lease_time ] [ -R {on|off|host[+host]} ] [ -g on | off ] [ -x xtend_cnt ] [ -P SS_pathname ] [ -G add | remove ]

Description

The chnfs command invokes the number of nfsd daemons specified. The chnfs command does this by changing the objects in the SRC database. The chnfs command also is used to enable or disable the use of advanced security methods by NFS or to enable or disable the use of NFS Version 4. These changes take place at different times depending on the flags chosen.

Note: The chnfs command does not change the number of biod threads. To change the number of biod threads, use the NFS-specific -o biods=n option of the mount command. For example, to specify that an NFS mount use 16 biod threads, type:

mount -obiods=16 server:/tmp /mnt

By default, a v2 mount uses 7 biod threads, and a v3 mount and a v4 mount use 32 biod threads.

Flags

Item	Description
-B	Temporarily stops the daemons currently running on the system, modifies the SRC database code to reflect the new number, and restarts the daemons indicated. This flag is a default.
-b NumberofBiod	Specifies the number of biod threads on the client. This option has no effect and should not be used.
-G add \| remove	Controls the NFSv4 Grace Period bypass. When `add` is specified as the value of this flag, the grace period is bypassed regardless of how the -g option is specified and the -gpbypass flag is added to the nfsd argument. When `remove` is specified as the value of this flag, the -gpbypass flag is removed from the nfsd argument.
-g on\|off	Controls the NFSv4 Grace Period enablement. The possible values are `on` or `off`. When no -g option is specified, the grace period is disabled by default.
-I	Changes the objects in the SRC database so that the number of daemons specified will be run during the next system restart.
-L v4_lease_time	Specifies the lease time that the state manager uses when granting a lock to a client. This flag sets the NFS Version 4 lease time in seconds. The lease time also affects the length of the grace period, the time when a client is deemed dead or expired, and the duration of time that a client has before getting timed out. The valid range is from 10 to 600 seconds. The default value is 120 seconds. This flag is valid only for NFS Version 4.
-l NumberOfLockd	Specifies the number of lockd daemons to run on the system.
-N	Temporarily stops the daemons currently running on the system and restarts the number of daemons indicated.
-n NumberOfNfsd	Specifies the number of nfsd daemons to run on the system.
P SS_pathname	Specifies the location for stable storage. If grace period is enabled, the state manager begins logging in state information in this pathname. If the filesystem is small, the state manager also allocates space initially. The default location for the stable storage pathname is /var/adm/nfsv4.
-p v4_public_node	Changes the NFS Version 4 public directory to the specified directory. The directory must be a subdirectory of the root directory. The public directory cannot be changed if any directories are currently exported for Version 4 use.
-R {on\|off\|host[+host]}	Enables or disables NFS Version 4 replication. If replication is enabled, replica locations can be specified for Version 4 exports. If replication is not enabled, attempts to export a directory with replica locations will fail. If any directories are exported for NFS Version 4 use, the replication mode cannot be changed. Changing the replication mode of the NFS server can cause errors on clients holding filehandles issued under the previous replication mode. If the host[+host] form is used, replication is enabled and the host list is used as the replica locations for the nfsroot.
-r v4_root_node	Changes the NFS Version 4 root location to the specified directory. Version 4 clients that mount / will see the specified directory as the server's root. The public directory cannot be changed if any directories are currently exported for Version 4 use.
-S	Enable RPCSEC_GSS. This enables NFS to use the enhanced security offered by RPCSEC_GSS, such as Kerberos 5.
-s	Disable RPCSEC_GSS. This disables the use of RPCSEC_GSS methods by NFS.
-V	Enable NFS Version 4.
-v	Disable NFS Version 4.
-x xtend_cnt	Controls the NFSv4 Grace Period automatic extension. The extend_cnt parameter specifies the total number of automatic extensions allowed for the grace period. If no -x option is specified, the number of allowed automatic extensions defaults to `1`. A single extension cannot extend the grace period for more than the length of the NFSv4 lease period. The NFSv4 subsystem uses runtime metrics (such as the time of the last successful NFSv4 reclaim operation) to detect reclamation of the state in progress, and extends the grace period for a length of time up to the duration of the given number of iterations.

Examples

To set the number of nfsd daemons to 10, enter:

chnfs    -n    10    -I

This change will be made for the next system restart.

Security

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.