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HP OpenVMS Systems Documentation

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HP OpenVMS System Management Utilities Reference Manual


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EXIT

Stops execution of SCACP and returns control to the DCL command level. You can also enter Ctrl/Z at any time to exit.

Format

EXIT


Parameters

None.

Qualifiers

None.

Example


SCACP> EXIT
$
      

This command stops execution of SCACP and returns control to the DCL command level.

HELP

Provides online help information about the SCACP utility.

Format

HELP [topic]


Parameter

topic

Specifies a subject for which you want information: an SCACP command or a command plus a command keyword. If you enter the HELP command with a command name only, such as HELP SET, SCACP displays a list of all of the command keywords used with the SET command.

Qualifiers

None.

Example


SCACP> HELP SET TRACE
      

The HELP command in this example displays information about the SET TRACE command.

SET CHANNEL

Sets CHANNEL management parameters, currently limited to priority values.

Note

If a LAN device is disabled for use by cluster communications, all channels associated with that device are deleted. This means that all management settings for that device and its associated channels will be deleted.

Format

SET CHANNEL nodename


Parameter

nodename[,...]

Includes channels to specific nodes, which you can use wildcards to specify. Each node name can be accompanied by optional qualifiers to specify local and remote device names. If no local or remote device name is specified, all channels to the specified node name are included.

Use the SHOW CHANNEL command to display node names and local and remote device names.


Qualifiers

/EXCLUDE=(nodename[,...])

Excludes channels to specific nodes, which you can use wildcards to specify. Each node name can be accompanied by optional qualifiers to specify local and remote device names. If no local or remote device name is specified, all channels associated with the specified node are included.

/LOCAL_DEVICE=(landevicename[,...])

Specifies a LAN device that identifies the local end of the channel; you can use wildcards to specify LAN devices.

Use the SHOW CHANNEL command to display node names and local and remote device names, or use the SHOW LAN_DEVICE command to display device names.

/PRIORITY=n

Sets the management priority value for channels to selected nodes. n can be a value between -128 and +127. Suggested values are:
2 to cause channels to be preferred
-2 to exclude channels

Note

Starting with OpenVMS Version 7.3-2, a channel whose priority is -128 is not used for cluster communications. The priority of a channel is the sum of the management priority assigned to the local LAN device and the channel itself. Therefore, you can assign any combination of channel and LAN device management priority values to achieve a total of -128.

Caution

If you set the priority of all channels to -128, you totally disable use of the LAN for cluster communication. This can cause the system to CLUEXIT.

/REMOTE_DEVICE=(landevicename[,...])

Specifies a LAN device that identifies the remote end of the channel; you can use wildcards to specify LAN devices.

Use the SHOW CHANNEL command to display node names and local and remote device names, or use the SHOW LAN_DEVICE command to display device names.

Use the SHOW LAN_DEVICE command on the remote node to display remote device names.


Examples

#1

SCACP> SET CHANNEL/PRIORITY=3 NODE5
      

The command in this example sets the priorities of all channels to node NODE5 to 3.

#2

SCACP> SET CHANNEL/LOCAL=EWA/REMOTE=EWB -
_SCACP> NODE10,NODE15/L=F*/R=F*,NODE20/PRIORITY=10
      

The command in this example is equivalent to the following command:


SET CHANNEL NODE10/L=EWA/R=EWB,NODE15/L=F*/R=F*,NODE20/L=*/R:*/PRIORITY=10

This command sets the priority of the following channels to 10:

  • To node NODE10, the channel with local device EWA and remote device EWB
  • To node NODE15, the channels with local LAN devices starting with F and remote LAN devices starting with F
  • All channels to node NODE20

SET CIRCUIT

Sets the circuit management priority value.

Note

If a circuit is closed, it is deleted. This means that the management settings for that circuit are also deleted. If the circuit is opened again, it has the default values for its management settings.

Format

SET CIRCUIT nodename


Parameter

nodename[,...]

Names a circuit or circuits to specific nodes, which you can use wildcards to specify. You can qualify each node name with additional parameters to uniquely identify a single circuit.

Qualifiers

/EXCLUDE=(nodename[/PORT=portname[/RSTATION=n]][,...])

Allows you to exclude a specific circuit to a node. If multiple circuits to the same node exist, you can use the /PORT and /RSTATION qualifiers to uniquely identify the circuit.

/PORT=portname[/RSTATION=n]

If multiple circuits to the same node exist, you can use the /PORT and /RSTATION qualifiers to uniquely identify the circuit. You can use the /RSTATION qualifier only in conjunction with the /PORT qualifier.

Example


SCACP> SET CIRCUIT CLUIO1 /PORT=PIB0 /PRI=10
      

The command in this example sets the priority of the circuit to node CLUIO1 through PIB0 to 10. You need to use the /PORT qualifier if multiple circuits to node CLUI01 exist and only the circuit through PIB0 is meant to have its priority raised.

SET LAN_DEVICE

Sets device management priority parameter.

Format

SET LAN_DEVICE landevicename


Parameter

landevicename[...,]

Includes specific LAN devices, which you can use wildcards to specify.

Use the /EXCLUDE qualifier to exclude LAN devices.

Use the SHOW LAN_DEVICE command to display device names.


Qualifiers

/EXCLUDE=(landevicename1[,...])

Excludes one or more specific LAN devices, which you can use wildcards to specify.

/PRIORITY=n

Sets the management priority value for the selected devices. n can be a value between -128 and +127. Suggested values are:
2 to cause devices to be preferred
-2 to exclude devices

Note

Starting with OpenVMS Version 7.3-2, a channel whose priority is -128 is not used for cluster communications. The priority of a channel is the sum of the management priority assigned to the local LAN device and the channel itself. Therefore, you can assign any combination of channel and LAN device management priority values to achieve a total of -128.

Caution

If you set the priority of all devices to -128, you totally disable use of the LAN for cluster communication. This can cause the system to CLUEXIT.

Example


SCACP> SET LAN_DEVICE/PRIORITY=3 EWA
      

The command in this example sets the management priority for device EWA to 3.

SET PORT

Sets a port management priority value.

Format

SET PORT portname


Parameter

portname[,...]

Specifies SCA port names, in which you can include wildcards.

Use the /EXCLUDE qualifier to exclude specific ports.

Use the SHOW PORT command to display all ports available on your system.


Qualifiers

/EXCLUDE=(portname[,...])

Excludes specific ports from the operation.

/PRIORITY=n

Sets the management priority value for the selected ports. n can be any value between -128 and +127.

Examples

#1

SCACP> SET PORT PEA0/PRIORITY=5
      

The command in this example sets the management priority for the PEA0 port to 5.

#2

SCACP> SET PORT PEA0 /PRIORITY=5 /EXCLUDE=PEA0
      

The command in this example sets all ports with the exception of PEA0 to a management priority of 5.

SET TRACE

SET TRACE sets or modifies PEdriver tracing parameters.

Note

This command is reserved for use by HP Services and OpenVMS Engineering only. Trace commands and output are subject to change from release to release.

Format

SET TRACE nodename


Parameter

nodename[,...]

Includes channels and VCs to specific nodes, which you can use wildcards to specify. Each node name can be accompanied by optional qualifiers to specify local and remote device names.

If no local or remote device name is specified, all channels associated with the specified node are included, as well as the VC to the specified node.

Use the SHOW CHANNEL command to display node names and local and remote device names.


Qualifiers

/AFTER=n

After the trace stop condition has been satisfied, continue tracing for n events, and then stop. If you do not specify /AFTER, tracing does not continue after the trace stop event. n can be any value between 0 and FFFFFFF.

/DEFAULT

Sets the trace context back to the default settings, which are:


       trace all channels and VCs
       /AFTER=0
       /EVENT=default settings
       /STOP
       /SIZE=512

/EVENT=(event1[,...])

Enables tracing on specific events, which you can use wildcards to specify. The default is a subset of the events, which includes most errors and state changes when the system parameter SYSTEM_CHECK is set to 0. The default is "all events included" when SYSTEM_CHECK is set to 1.

Use the SHOW TRACE/CONTEXT command to display event names.

/EXCLUDE=(nodename[/LOCAL_DEVICE=landevicename] [/REMOTEDEVICE=landevicename][,...])

Excludes VCs or channels, or both, to specific nodes, which you can use wildcards to specify. Each node name can be accompanied by optional qualifiers to specify local and remote device names. If no local or remote device name is specified, the VC and all channels associated with the specified node are excluded.

/LOCAL_DEVICE=(landevicename[,...])

Includes specific LAN devices that identify the local end of the channel. You can use wildcards to specify LAN devices.

/REMOTE_DEVICE=(landevicename[,...])

Includes specific LAN devices that identify the remote end of the channel; you can use wildcards to specify LAN devices.

Use the SHOW LAN_DEVICE command to display device names.

/STOP=(event1[,...])

Stops tracing on specific events, which you can use wildcards to specify. The default is "no events included."

Use the SHOW TRACE/CONTEXT command to display event names.

/SIZE=n

Specifies a trace buffer size of n bytes to be used by PEdriver for each trace buffer: one for global PEdriver use, one for each selected channel, and one for each selected VC. n can be any value between 0 and FFFFFFF.


Examples

#1

SCACP> SET TRACE/EVENT=CC_STATE/SIZE=1000
      

The command in this example specifies that the trace buffers for each channel, VC, and the global buffer each be 1000 bytes in length.

#2

SCACP> SET TRACE/EVENT=* NODE10/LOCAL=EWA,NODE20
      

The command in this example specifies that all events are to be recorded; when applicable to a particular node, however, only channels and VCs to nodes NODE10 and NODE20 are to be included.

#3

SCACP> SET TRACE/EVENT=(ALL,NOTIMER) NODE10
      

The command in this example specifies that all events except timer events on node NODE10 are to be included.

#4

SCACP> SET TRACE/LOCAL=EWA/REMOTE=EWB
NODE10,NODE15/L=F*/R=F*,NODE20
      

The command in this example is equivalent to the following command:


SET TRACE NODE10/L=EWA/R=EWB,NODE15/L=F*/R=F*,NODE20/L=EWA/R:EWB

The command in the example sets tracing on the following channels:

  • On node NODE10, channels with local device EWA and remote device EWB
  • On node NODE15, channels with local LAN device starting with F and remote LAN device starting with F
  • On node NODE20, channels with local LAN device EWA and remote LAN device EWB

SET VC

Sets values for the virtual circuit management parameters (checksumming, compression, ECS delay threshold, transmit window size, and receive window size values).

Format

SET VC nodename


Parameter

nodename[,...]

Includes VCs to specific nodes, which you can use wildcards to specify.

Use the /EXCLUDE qualifier to exclude VCs to specific nodes.

Use the SHOW CHANNEL or SHOW VC command to display VC names, which are simply the names of remote nodes.


Qualifiers

/CHECKSUMMING

/NOCHECKSUMMING

Enables or disables checksum verification on the selected VCs to the specified nodes.

You can use this command alone or in combination with the system parameter NISCS_PORT_SERV. (For more information, see online help for NISCS_PORT_SERV.)

Note that the the SET VC/CHECKSUMMING setting is not valid beyond the life of the system. Therefore, you might want to include SET VC/CHECKSUMMING commands in your startup file, or reissue these commands at the next boot.

/COMPRESSION

/NOCOMPRESSION

Enables or disables sending compressed data by the specified VCs. The default is /NOCOMPRESSION.

Usage notes:

  • Compression is used only if the partner node has a PEdriver version that supports it.
  • You can also enable the use of compression with the NISCS_PORT_SERV system parameter. For more information about NISCS_PORT_SERV, see the System Parameter appendix in this manual.
  • The /NOCOMPRESSION qualifier does not override compression enabled by setting bit 2 of NISCS_PORT_SERV.

/ECS_MAX_DELAY=n

/NOECS_MAX_DELAY

Sets a management-specified lower bound on the maximum delay (in microseconds) an ECS member channel can have. The value for n can be any value between 0 and 3000000. /NOECS_MAX_DELAY disables a prior management delay setting.

You can use this command to override the PEdriver automatically calculated delay thresholds to ensure that all channels with delays less than the value supplied for n are included in the VC's ECS.

The command operates as follows: Whenever at least one tight peer channel has a delay of less than the management-supplied value, all tight peer channels with delays less than the management-supplied value are automatically included in the ECS. When all tight peer channels have delays equal to or greater than the management setting, the ECS membership delay thresholds are automatically calculated and used. The /NOECS_MAX_DELAY qualifier disables management control by setting the management delay value to zero.

You must determine an appropriate value for your configuration by experimentation. An initial value of 2000 (2 ms) to 5000 (5 ms) is suggested.

CAUTION

By overriding the automatic delay calculations, you can include a channel in the ECS whose average delay is consistently greater than 1.5 to 2 times the average delay of the fastest channels. When this occurs, the overall VC throughput becomes the speed of the slowest ECS member channel.

An extreme example is when the management delay permits a 10 Mb/s Ethernet channel to be included with multiple 1 Gb/s channels. The resultant VC throughput drops to 10 Mb/s.

Note that the SET VC/ECS_MAX_DELAY setting is not valid beyond the life of the system. Therefore, you might want to include SET VC/ECS_MAX_DELAY commands in your startup file or reissue these commands at the next boot.

/EXCLUDE=(nodename[,...])

Excludes VCs to specific nodes, which you can use wildcards to specify.

/WINDOW=RECEIVE=n

/WINDOW=NORECEIVE

Sets a management-specified upper bound on the receive window size (that is, the number of out-of-order packets this VC holds in its resequencing cache while awaiting the next in-order packet or packets).

You can use this qualifier to override the automatically calculated receive window size. This ensures that the VC has enough buffering to receive the expected maximum number of out-of-order packets.

Usage notes:

  • The window size value n must be an exact power of 2.
    Never use settings that cause the receive window of a VC to be smaller than the transmit window of the partner node. Otherwise, the partner can send packets that cannot be cached when a packet is lost. This results in unnecessary retransmissions, and might cause channels not to be used because they become "lossy." This leads to the remaining restrictions listed.
  • Always decrease the receive window size of a VC's partner node before decreasing a VC's receive window size.
    HP recommends using SYSMAN to decrease both the local and the remote VC transmit window sizes before increasing the local and remote receive window sizes (as shown in the example).
  • Always increase the receive window size of a VC's partner node before increasing a VC's transmit window size.
    HP recommends using SYSMAN to increase both the local and the remote VC receive window sizes before increasing the local and remote transmit window sizes.
  • Whenever you enter the SET VC/WINDOW=RECEIVE command, the following sequence of events occurs:
    1. The VC's current resequencing cache is emptied.
    2. The VC partner node automatically retransmits any discarded packets.
    3. As a result of 2, the VC and channel retransmit counts increase.
    4. A few messages similar to the following might be displayed, indicating that one or more channels has temporarily become "lossy":


          %PEA0, Excessive packet losses on LAN Path from EWA to EWC
                 on REMOTE NODE STAR
      
    5. The partner node recovers automatically within a few seconds.
  • You can use the SCACP> CALCULATE WINDOW_SIZE command to assist you in selecting the size to use for transmit and receive windows.

/WINDOW=TRANSMIT=n

/WINDOW=NOTRANSMIT

Sets a management-specified upper bound on the transmit window size (that is, the number of out-of-order packets this VC sends while awaiting acknowledgment of the transmitted packets) to n. The /WINDOW=NOTRANSMIT qualifier resumes automatic control of the window size and changes the management transmit window size to zero.

You can use the /WINDOW=TRANSMIT qualifier to override the automatically calculated transmit window size to ensure that the VC has enough buffering to receive the expected maximum number of out-of-order packets.

Usage notes:

  • The window size value n must be an exact power of 2.
    Never use settings that cause the receive window of a VC to be smaller than the transmit window of the partner node. Otherwise, the partner can send packets that cannot be cached when a packet is lost. This results in unnecessary retransmissions, and might cause channels not to be used because they become "lossy". This leads to the following restrictions.
  • Always decrease the transmit window size of a VC's partner node before decreasing a VC's receive window size.
    HP recommends using SYSMAN to decrease both the local and the remote VC transmit window sizes before increasing the local and remote receive window sizes.
  • Always increase the receive window size of a VC's partner node before increasing a VC's transmit window size.
    HP recommends using SYSMAN to increase both the local and the remote VC receive window sizes before increasing the local and remote transmit window sizes (as shown in the example).
  • You can use the SCACP CALCULATE WINDOW_SIZE command to assist you in selecting the size to be used for transmit and receive windows.

Examples

#1

 $RUN SYS$SYSTEM:SYSMAN
SYSMAN> SET ENV/NODE=LARRY
 DO MC SCACP SET VC LARRY/WINDOW=TRANSMIT=16
 SET ENV/NODE=CURLY
 DO MC SCACP SET VC CURLY/WINDOW=TRANSMIT=16
 SET ENV/NODE=LARRY
 DO MC SCACP SET VC LARRY/WINDOW=RECEIVE=16
 SET ENV/NODE=CURLY
 DO MC SCACP SET VC CURLY/WINDOW=RECEIVE=16
 EXIT
      

This example shows how to decrease window size. The transmit and receive window sizes are 32 on both nodes, and the commands decrease the window size for the VC between LARRY and CURLY. (You can enter the commands on either node.)

#2

 $RUN SYS$SYSTEM:SYSMAN
SYSMAN> SET ENV/NODE=LARRY
 DO MC SCACP SET VC LARRY/WINDOW=RECEIVE=64
 SET ENV/NODE=CURLY
 DO MC SCACP SET VC CURLY/WINDOW=RECEIVE=64
 SET ENV/NODE=LARRY
 DO MC SCACP SET VC LARRY/WINDOW=TRANSMIT=64
 SET ENV/NODE=CURLY
 DO MC SCACP SET VC CURLY/WINDOW=TRANSMIT=64
 EXIT
      

This example shows how to increase window size. The transmit and receive window sizes are 32 on both nodes, and the commands increase the window size for the VC between LARRY and CURLY. (You can enter the commands on either node.)


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