nfso Command

Purpose

Manages Network File System (NFS) tuning parameters.

Syntax

nfso [ -p | -r ] [ -c ] { -o Tunable[ =newvalue ] }

nfso [ -p | -r ] { -d Tunable }

nfso [ -p | -r ] -D

nfso [ -p | -r ] -a [-F] [ -c ]

nfso -h [ Tunable ]

nfso -l [ hostname ]

nfso [-F] -L [ Tunable ]

nfso [-F] -x [ Tunable ]

nfso [ -@ WparName ] [ -p | -r ] -a [ -c ]

nfso [ -@ WparName ] [ -p | -r ] [ -c ] { -o Tunable[ =newvalue ] }

Description

Use the nfso command to configure Network File System tuning parameters. The nfso command sets or displays current or next boot values for Network File System tuning parameters. This command can also make permanent changes or defer changes until the next reboot. Whether the command sets or displays a parameter is determined by the accompanying flag. The -o flag performs both actions. It can either display the value of a parameter or set a new value for a parameter.

Understanding the Effect of Changing Tunable Parameters

Extreme care should be taken when using this command. If used incorrectly, the nfso command can make your system inoperable.

Before modifying any tunable parameter, you should first carefully read about all its characteristics in the Tunable Parameters section below, and follow any Refer To pointer, in order to fully understand its purpose.

You must then make sure that the Diagnosis and Tuning sections for this parameter truly apply to your situation and that changing the value of this parameter could help improve the performance of your system.

If the Diagnosis and Tuning sections both contain only "N/A", you should probably never change this parameter unless specifically directed by AIX® development.

Flags

NAME                      CUR    DEF    BOOT   MIN    MAX    UNIT           TYPE
     DEPENDENCIES
--------------------------------------------------------------------------------
portcheck                 0      0      0      0      1      On/Off            D
--------------------------------------------------------------------------------
udpchecksum               1      1      1      0      1      On/Off            D
--------------------------------------------------------------------------------
nfs_socketsize            600000 600000 600000 40000  1M     Bytes             D
--------------------------------------------------------------------------------
nfs_tcp_socketsize        600000 600000 600000 40000  1M     Bytes             D
--------------------------------------------------------------------------------
... 
where: 
    CUR = current value 
    DEF = default value 
    BOOT = reboot value 
    MIN = minimal value 
    MAX = maximum value 
    UNIT = tunable unit of measure 
    TYPE = parameter type: D (for Dynamic), 
           S (for Static), R (for Reboot),B (for Bosboot), M (for Mount),
           I (for Incremental), C (for Connect), and d (for Deprecated) 
    DEPENDENCIES = list of dependent tunable parameters, one per line

tunable,current,default,reboot,min,max,unit,type,{dtunable } 

where: 
    current = current value 
    default = default value 
    reboot = reboot value 
    min = minimal value 
    max = maximum value 
    unit = tunable unit of measure 
TYPE = parameter type: D (for Dynamic), 
           S (for Static), R (for Reboot),B (for Bosboot), M (for Mount),
           I (for Incremental), C (for Connect), and d (for Deprecated) 
       dtunable = space separated list of dependent tunable parameters 

If you make any change (with -o, -d or -D) to a restricted tunable parameter, it results in a warning message that a tunable parameter of the restricted-use type has been modified. If you also specify the -r or -p options on the command line, you are prompted for confirmation of the change. In addition, at system reboot, the presence of restricted tunables in the /etc/tunables/nextboot file, which were modified to a value that is different from their default value (using a command line specifying the -r or -p options), results in an error log entry that identifies the list of these modified tunables.

If you make any change (with -o, -d, or -D) to a parameter of type Mount, it results in a warning message that the change is only effective for future mountings.

If you make any change (with -o, -d or -D) to a parameter of type Connect, it results in inetd being restarted, and a warning message that the change is only effective for future socket connections.

If you make any change (with -o, -d, or -D) to a parameter of type Bosboot or Reboot without -r, it results in an error message.

If you make any change (with -o, -d, or -D but without -r) to the current value of a parameter of type Incremental with a new value smaller than the current value, it results in an error message.

• nfs_dynamic_retrans
• nfs_iopace_pages
• nfs_use_reserved_port
• nfs_v4_fail_over_timeout
• utf8_validation
• nfs_auth_rbr_trigger
• client_delegation

Tunable Parameters Type

Note that the current set of parameters managed by the nfso command only includes Dynamic, Mount, and Incremental types.

Compatibility Mode

When running in pre 5.2 compatibility mode (controlled by the pre520tune attribute of sys0, see AIX 5.2 compatibility mode), reboot values for parameters, except those of type Bosboot, are not really meaningful because in this mode they are not applied at boot time.

In pre 5.2 compatibility mode, setting reboot values to tuning parameters continues to be achieved by imbedding calls to tuning commands in scripts called during the boot sequence. Parameters of type Reboot can therefore be set without the -r flag, so that existing scripts continue to work.

This mode is automatically turned ON when a machine is MIGRATED to AIX 5L™ Version 5.2. For complete installations, it is turned OFF and the reboot values for parameters are set by applying the content of the /etc/tunables/nextboot file during the reboot sequence. Only in that mode are the -r and -p flags fully functional. See Kernel Tuning in the AIX Version 7.1 Performance Tools Guide and Reference for details about the new 5.2 mode.

Tunable Parameters

For default values and range of values for tunables, refer the nfso command help (-h <tunable_parameter_name>).

Examples

1. To set the portcheck tunable parameter to a value of zero, type:

   nfso -o portcheck=0

2. To set the udpchecksum tunable parameter to its default value of 1 at the next reboot, type:

   nfso -r -d udpchecksum

3. To print, in colon-delimited format, a list of all tunable parameters and their current values, type:

   nfso -a -c

4. To list the current and reboot value, range, unit, type and dependencies of all tunables parameters managed by the nfso command, type:

    nfso -L

5. To display help information on nfs_tcp_duplicate_cache_size, type:

   nfso -h nfs_tcp_duplicate_cache_size

6. To permanently turn off nfs_dynamic_retrans, type:

   nfso -p -o nfs_dynamic_retrans=0

7. To list the reboot values for all Network File System tuning parameters, type:

   nfso -r -a

8. To list (spreadsheet format) the current and reboot value, range, unit, type and dependencies of all tunables parameters managed by the nfso command, type:

   nfso -x