|
HP OpenVMS System Manager's Manual, Volume 2:... |
Managing System Parameters |
|
|
| |
Modifying System Parameters with AUTOGEN
This command instructs AUTOGEN to perform the following actions:$@SYS$UPDATE:AUTOGEN SAVPARAMS TESTFILES
This AUTOGEN command runs SYSMAN to update the new system parameter values and installs them on the system when it is rebooted.$@SYS$UPDATE:AUTOGEN GENPARAMS REBOOT
Controlling AUTOGEN's Parameter Settings
with MODPARAMS.DAT
If, after examining the AGEN$PARAMS.REPORT or SETPARAMS.DAT
file, you decide to correct hardware configuration data or modify
system parameter values chosen by AUTOGEN, edit the MODPARAMS.DAT
file as described in this section to manually specify parameter
values.
 | Always edit MODPARAMS.DAT to specify values for parameters. Do not edit PARAMS.DAT; modifying the contents of this file might prevent AUTOGEN from operating correctly. |
You can define symbols in MODPARAMS.DAT using the following formats to control parameter values:
| Control Method | Symbol Format | For More Information |
|---|---|---|
|
Increase a
value by a specified amount
|
ADD_*
|
Increasing a Value with the ADD_ Prefix
|
|
Specify a minimum
value
|
MIN_*
|
Specifying a Minimum Value with the MIN_ Prefix
|
|
Specify a maximum
value
|
MAX_*
|
Specifying a Maximum Value with the MAX_ Prefix
|
|
Specify an absolute value
|
Parameter name
|
Specifying an Absolute Value
|
When defining symbols in MODPARAMS.DAT, make sure to adhere to the following criteria:
| When AUTOGEN reads MODPARAMS.DAT or any other parameter
file, it checks to determine if the symbol names specified in the
file are valid. If they are not, AUTOGEN writes a warning message
to AGEN$PARAMS.REPORT. However, AUTOGEN checks only the symbol name;
it does not check the validity of the value specified for the symbol. If a value is invalid, the line is not ignored. AUTOGEN attempts to use the specified value. A symbol is not checked if it is specified in a line that contains a DCL expression other than the equal sign (=). For example, AUTOGEN does not check the validity of a symbol name specified in a line with the DCL IF statement. Instead, AUTOGEN writes a warning message to AGEN$PARAMS.REPORT. |
Increasing
a Value with the ADD_ Prefix
Use the ADD_ prefix to increase the value of any numeric parameter.
The new values are updated in subsequent AUTOGEN calculations during
the GENPARAMS phase. The following example demonstrates the use
of the ADD_ prefix:
ADD_GBLPAGES=500 ADD_NPAGEDYN=10000An ADD_ parameter record for a parameter that AUTOGEN calculates will add the value to AUTOGEN's calculations. An ADD_ parameter record for a parameter that AUTOGEN does not calculate will add the value to the parameter's default (not current) value. (Refer to the AUTOGEN section in HP OpenVMS System Management Utilities Reference Manual: A--L for a table of parameters affected by AUTOGEN.)
 | The ADD_ value is added to the calculated value once,
and does not accumulate with successive runs for feedback calculations. Typically, you would not use the ADD_ prefix for modifying parameters that are calculated by the feedback mechanism, because the feedback results should accurately reflect your work load. However, if you do use the ADD_ prefix with feedback, AUTOGEN adds a value only once if AUTOGEN is run to the SETPARAMS phase or beyond. To maintain a minimum level above AUTOGEN's calculation, use the MIN_ prefix. |
Specifying
a Minimum Value with the MIN_ Prefix
Use the MIN_ prefix if you do not want AUTOGEN to set a parameter
below a specified value. MIN_ refers to the minimum value to which
a parameter can be set by AUTOGEN. The following example sets the
minimum value to 400,000:
MIN_PAGEDYN = 400000
Specifying
a Maximum Value with the MAX_ Prefix
Use the MAX_ prefix if you do not want AUTOGEN to set a parameter
above a specified value. MAX_ refers to the maximum value to which
a parameter can be set by AUTOGEN. The following example sets the maximum
value to 400,000:
MAX_PAGEDYN = 400000
Specifying
an Absolute Value
Use this method to specify a value for a parameter that AUTOGEN
does not calculate. (Refer to the AUTOGEN section of HP OpenVMS System Management Utilities Reference Manual: A--L for
a table of the system parameters modified in AUTOGEN calculations.)
| HP strongly recommends that you use this method only
for parameters that describe the system environment (for example,
SCSNODE and SCSSYSTEMID). For the parameters that AUTOGEN calculates,
specifying a value with this method disables AUTOGEN's calculations. Instead
of specifying an absolute value, use one of the following methods:
|
For example, the following command assigns the node name BIGVAX to the SCSNODE parameter:
SCSNODE = "BIGVAX" ! the node name
| String values must be within quotation marks (""). |
Defining the Number of VAXcluster Nodes (VAX
Only)
In a VAXcluster environment, use the NUM_NODES symbol to prevent
temporary changes in VAXcluster membership from affecting AUTOGEN's
calculation of VAXcluster-related parameter values. Define the NUM_NODES
symbol in MODPARAMS.DAT to specify the number of nodes that are
to run in the VAXcluster. AUTOGEN uses this value to set parameters
that are affected by the number of VAXcluster nodes. For example,
include the following line in MODPARAMS.DAT:
NUM_NODES = 30
Defining the Number of Ethernet Adapters
(VAX Only)
In a VAXcluster environment, define the NUM_ETHERADAPT symbol
in MODPARAMS.DAT to specify the total number of Ethernet adapters
in the VAXcluster system. For example, include the following line
in MODPARAMS.DAT:
NUM_ETHERADAPT = 40
Presetting Parameter Values Before Adding
Memory (VAX Only)
On VAX systems, if you plan to upgrade your system hardware
by adding a large amount (512 MB or more) of memory, you might want
to preset your system parameters to values appropriate for the additional
memory. Presetting your system parameters minimizes the possibility
of memory upgrade problems caused by inappropriate parameter values.
How to Perform This Task
Perform the following steps:
MEMSIZE = 2048 * 1024 ! (2048 page per MB * 1GB of memory)
Overriding Parameters Related to DECnet
To
override AUTOGEN's observations regarding the presence (or absence)
of DECnet, set the MODPARAMS.DAT parameter LOAD_DECNET_IMAGES to
TRUE (or FALSE). Controlling the setting is useful for sites that
have no synchronous network hardware but want to run asynchronous
DECnet.
Values Set for NPAGEDYN and NPAGEVIR
For the benefit of OpenVMS VAX systems with limited physical
memory, AUTOGEN logs a warning message in its report if NPAGEDYN
exceeds 10 percent of physical memory or if NPAGEVIR exceeds 33
percent of physical memory.
AUTOGEN also limits its own calculated value for NPAGEDYN to 20 percent of physical memory, and limits NPAGEVIR to 50 percent of physical memory. These calculated values are adequate for most workstations and systems with 16 or fewer megabytes of physical memory. If your system requires a larger value, you can override the AUTOGEN calculated values by setting higher values in MODPARAMS.DAT.
Specifying a Minimum Required Age for Feedback
(VAX Only)
On VAX systems, AUTOGEN feedback is useful only when a system
has been running long enough to accurately reflect the system's
normal work load. By default, AUTOGEN uses feedback if the data
is older than 24 hours. On VAX systems, you can define the logical
name AGEN$FEEDBACK_REQ_TIME to specify, in hours, a different minimum
age required for feedback. AUTOGEN uses this value to determine
whether the feedback is to be used.
For example, you might define the logical name as follows, to indicate that AUTOGEN should use feedback if it is older than 19 hours:
To define this logical name each time the system starts up, add this command to SYLOGICALS.COM.$DEFINE/SYSTEM AGEN$FEEDBACK_REQ_TIME 19
Including an External Parameter File in MODPARAMS.DAT
You
can include external parameter files in MODPARAMS.DAT. For example,
you might want to set a system parameter to the same value on all
nodes in a VAXcluster or an OpenVMS Cluster environment; you might also
want to specify node-specific values for other system parameters.
You could specify the cluster-common values in a separate cluster-common
file and include this cluster-common file in the MODPARAMS.DAT file on
each system in the cluster.
To include a parameter file, place a command in the following format in MODPARAMS.DAT, or in any parameter file that is included in MODPARAMS.DAT:AGEN$INCLUDE_PARAMS full-directory-spec:filename
Example
To include a cluster-common parameter file named CLUSTERPARAMS.DAT, create a common parameter file with the following name:
 | SYS$COMMON:[SYSEXE]CLUSTERPARAMS.DAT |
Add the following line in the MODPARAMS.DAT file in the system-specific directory of each cluster:
AGEN$INCLUDE_PARAMS SYS$COMMON:[SYSEXE]CLUSTERPARAMS.DAT
Turning
Off Logging of DCL Statements
The contents of MODPARAMS.DAT are evaluated as DCL statements;
you can make assignments to symbols with names that are not system
parameters (for example, scratch variables or conditional assignments
based on other values). Traditionally, every such assignment is
logged in AGEN$PARAMS.REPORT, sometimes creating a large file with
many logging statements that do not interest users.
You can prefix any assignments that you prefer not to log in AGEN$PARAMS.REPORT with a dollar sign ($). When AUTOGEN encounters a MODPARAMS.DAT record beginning with a dollar sign, it does not check the list of known system parameters and does not log this record to AGEN$PARAMS.REPORT.
|
|
