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HP OpenVMS System Management Utilities Reference
Manual
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
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
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.
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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.
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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.
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/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
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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
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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
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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.
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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
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SCACP> SET CIRCUIT CLUIO1 /PORT=PIB0 /PRI=10
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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.
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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.
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Example
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SCACP> SET LAN_DEVICE/PRIORITY=3 EWA
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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
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The command in this example sets the management priority for the PEA0
port to 5.
#2 |
SCACP> SET PORT PEA0 /PRIORITY=5 /EXCLUDE=PEA0
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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.
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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
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/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
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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
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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
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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
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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
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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.
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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:
- The VC's current resequencing cache is emptied.
- The VC partner node automatically retransmits any discarded packets.
- As a result of 2, the VC and channel retransmit counts increase.
- 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
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- 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
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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
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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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