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HP OpenVMS System Management Utilities Reference
Manual
ALF SHOW
Displays one or more records from the ALF database.
Requires read (R) and write (W) access to the SYSALF database
(SYS$SYSTEM:SYSALF.DAT).
Format
ALF SHOW [device]
Parameter
[device]
Specifies the terminal name or port name whose record you want to
display. You can use wildcard characters in the terminal name or port
name. Certain restrictions in wildcard matching of ALF records exist,
as shown in the examples section.
Qualifiers
/USERNAME=user
Displays the records held by the specified user. You can use wildcard
characters with this qualifier.
/OUTPUT[=filespec]
Directs the output of the command to a file. If you do not include a
file specification with this qualifier, SYSMAN writes the output to the
file SYSMAN.LIS in your default directory.
Description
The ALF SHOW command displays one or more records in the ALF database.
Examples
| #1 |
SYSMAN> ALF SHOW TTA* /USERNAME=MANESS /OUTPUT=ALF.TXT
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In this example, the records for all terminals named TTAx that are
assigned to user MANESS are selected and directed to the file ALF.TXT.
This command displays only those records that start with the string TTA.
This command displays only those records that start with the string
<nodename>$TTA.
This command displays records that have device names ending with TTA.
| #5 |
SYSMAN> ALF SHOW *TTA*
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This command displays all records that contain the string TTA.
ATTACH
Transfers control from your current process (which then hibernates) to
the specified process in your job.
The ATTACH and SPAWN commands cannot be used if your terminal has an
associated mailbox.
Format
ATTACH [process-name]
Parameter
process-name
Specifies the name of a parent process or a spawned subprocess to which
control passes. The process must already exist, be part of your current
job tree, and share the same input stream as your current process.
However, the process cannot be your current process or a subprocess
created with the /NOWAIT qualifier.
Process names can contain from 1 to 15 alphanumeric characters. If a
connection to the specified process cannot be made, an error message is
displayed.
Qualifier
/PARENT
Enables you to attach to the parent process. If no parent process
exists, you receive an error message.
Description
The ATTACH command connects your input stream to another process. You
can use the ATTACH command to change control from one subprocess to
another subprocess or to the parent process.
When you enter the ATTACH command, the parent process goes into
hibernation and your input stream connects to the specified destination
process. You can use the ATTACH command to connect to a subprocess that
is part of a current job (left hibernating as a result of the
SPAWN/WAIT command or another ATTACH command) as long as the connection
is valid. No connection can be made to the current process, to a
process that is not part of the current job, or to a process that does
not exist. If you attempt any of these connections, you receive an
error message.
You can also use the ATTACH command in conjunction with the SPAWN/WAIT
command to return to a parent process without terminating the created
subprocess. See the description of the SPAWN command for more details.
Example
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$ SPAWN
%DCL-S-SPAWNED, process SYSTEM_1 spawned
%DCL-S-ATTACHED, terminal now attached to process SYSTEM_1
$ RUN SYS$SYSTEM:SYSMAN
SYSMAN> ATTACH SYSTEM
%DCL-S-RETURNED, control returned to process SYSTEM
$
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In this example, the SPAWN command creates a subprocess (SYSTEM_1).
After you invoke SYSMAN and enter the ATTACH command, you transfer the
terminal's control back to the parent process (SYSTEM).
CLASS_SCHEDULE ADD
The ADD command creates a new scheduling class.
The class scheduler provides the ability to limit the amount of CPU
time that a system's users receive by placing users in scheduling
classes. Each class is assigned a percentage of the overall system CPU
time. As the system runs, the combined set of users in a class is
limited to the percentage of CPU execution time allocated to their
class.
Users might get some additional CPU time if the qualifier /WINDFALL is
enabled for their scheduling class. Enabling the qualifier /WINDFALL
allows the system to give a small amount of CPU time to a scheduling
class when the scheduling class's allotted time has been depleted, but
a free CPU is available.
Format
CLASS_SCHEDULE ADD class_name
Parameter
class_name
Specifies the name of the scheduling class. You must specify a class
name with the ADD command. The maximum length for this name is 16
characters.
Qualifiers
/ACCOUNT
Specifies which user is part of this scheduling class. This is part of
a user's SYSUAF record.
The syntax for this qualifier is as follows:
[/ACCOUNT = (name1, name2,...name"n")]
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/CPULIMIT
Defines the maximum amount of CPU time that this scheduling class can
receive for the specified days and hours. You must specify this
qualifier when adding a class.
The syntax for this qualifier is as follows:
/CPULIMIT = ([primary], [h1-h2=time%],[h1=time%],
[,...],[secondary],[h1-h2=time%],[h1=time%],[,...])
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The h1-h2=time% syntax allows you to specify a range of hours followed
by the maximum amount of CPU time (expressed as a percentage) to be
associated with this set of hours. The first set of hours after the
keyword PRIMARY specifies hours on primary days; the set of hours after
the keyword SECONDARY specifies hours on secondary days. The hours are
inclusive; if you class schedule a given hour, access extends to the
end of that hour.
/PRIMEDAYS
Allows you to define which days are primary days and which days are
secondary days.
The syntax for this qualifier is as follows:
[/PRIMEDAYS = ([no]day[,...])]
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You specify primary days as MON, TUE, WED, THU, FRI, SAT, and SUN. You
specify secondary days as NOMON, NOTUE, NOWED, NOTHU, NOFRI, NOSAT, and
NOSUN.
The default is MON through FRI and NOSAT and NOSUN. Any days omitted
from the list take their default value. You can use the DCL command,
SET DAY, to override the class definition of primary and secondary days.
/UIC
Specifies which users are part of this scheduling class. This is part
of a user's SYSUAF record.
The syntax for this qualifier is as follows:
[/UIC = (uic1,uic2,...uic"n")]
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/USERNAME
Specifies which user is part of this scheduling class. This is part of
a user's SYSUAF record.
The syntax for this qualifier is as follows:
[/USERNAME = (name1, name2,...name"n")]
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/WINDFALL
Specifies that all processes in the scheduling class are eligible for
windfall.
The syntax for this qualifier is as follows:
By enabling windfall, you allow processes in the scheduling class to
receive a "windfall", that is, a small percentage of CPU
time, when the class's allotted CPU time has been depleted, and a CPU
is idle. Rather than let the CPU remain idle, you might decide that it
is better to let these processes execute, even if it means giving them
more than their alloted time.
The default value is for windfall to be disabled.
Description
The format for the CLASS_SCHEDULE ADD command is as follows:
SYSMAN> CLASS_SCHEDULE ADD class_name
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You can use the /ACCOUNT, /UIC, or /USERNAME qualifier to specify which
users are to be part of a scheduling class.
The Class Scheduler Database
The class scheduler database is a permanent database that allows
OpenVMS to class schedule processes automatically after a system has
been booted and rebooted. This database resides on the system disk in
SYS$SYSTEM:VMS$CLASS_SCHEDULE.DATA. SYSMAN creates this file as an RMS
indexed file when the first scheduling class is created with the SYSMAN
command CLASS_SCHEDULE ADD.
You can have a common class scheduler database for all cluster nodes,
or you can have a separate database for one node or for a small group
of nodes. Using a common database can be helpful in simplifying system
management. However, you must be aware of the issues raised in the
following examples:
- Example 1
Within a single database---common or separate---you
can have only one set of parameters for each class. For example,
SYSMAN> SET ENV/NODE=X
SYSMAN> CLASS ADD class1 /USERNAME=(user1) /CPULIMIT=(0-2=100%,3-23=30%)
SYSMAN> SET ENV/NODE=Y
SYSMAN> CLASS ADD class1 /USERNAME=(user1) /CPULIMIT=(0-2=40%,3-23=20%)
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With a database that is common to both nodes X and Y, the second
command produces an error because you have given the same class
different parameters. With separate databases for nodes X and Y, the
second command works.
- Example 2
The system must also be able to assign a process to a
unique class. You can specify the same user---or other identifying
information---in several classes as long as you define these classes on
separate nodes. For example:
SYSMAN> SET ENV/NODE=X
SYSMAN> CLASS ADD class1 /USERNAME=(user1) /CPULIMIT=(0-2=100%,3-23=30%)
SYSMAN> SET ENV/NODE=Y
SYSMAN> CLASS ADD class2 /USERNAME=(user1) /CPULIMIT=(0-2=40%,3-23=20%)
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This example works on a database that is common to both nodes X and
Y because the two sets of parameters also have different class names.
The system can determine the class for user1 by checking the node on
which user1 is running.
- Example 3
The following example is incorrect on both common and
separate databases because the system cannot determine whether user1 is
a member of class1 or class2, since they are both defined for NODE X.
SYSMAN> SET ENV/NODE=X
SYSMAN> CLASS ADD class1 /USERNAME=(user1) /CPULIMIT=(0-2=100%,3-23=30%)
SYSMAN> CLASS ADD class2 /USERNAME=(user1) /CPULIMIT=(0-2=40%,3-23=20%)
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- Example 4
In addition to specifying nodes explicitly, as shown
in the preceding examples, you can also specify that a class applies to
the entire cluster. For example:
SYSMAN> SET ENV /CLUSTER
SYSMAN> CLASS ADD class1 /USERNAME=(user1) /CPULIMIT=(0-2=100%,3-23=30%)
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In this example, not only is class1 defined for all nodes in the
cluster, but class1 will also be defined for any node that you might
add to the cluster later---as long as the new node uses the same
database.
Note that if you define a class with the environment set
to CLUSTER, the command SYSMAN> CLASS SHOW/FULL lists that class
with the notation "Nodes: All Cluster Members," even if the database is
not common to all cluster nodes. To prevent confusion, HP recommends
using a common database.
Defining the Logical Name VMS$CLASS_SCHEDULE
If you wish to have a common class scheduler database on a cluster with
different system disks, or if you want to have a separate database for
each node on a cluster with a common system disk, on each node define
the system logical name VMS$CLASS_SCHEDULE to point to the location of
the database that you want that node to use. For example, in
SYSTARTUP_VMS.COM, include the following command:
$ DEFINE/SYSTEM VMS$CLASS_SCHEDULE disk:[directory]VMS$CLASS_SCHEDULE.DATA
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where:
disk:[directory] represents the disk and directory where you
want the database file to reside.
The Class Scheduler Database and Process Creation
By using a permanent class scheduler, a process is placed in a
scheduling class, if appropriate, at process creation time. When a new
process is created, the system determines whether this process belongs
to a scheduling class. To determine this, the system relies on data in
the SYSUAF file. Because the Loginout image already has information
about the process from this file, Loginout class-schedules the process
if it determines that the process belongs to a scheduling class.
Two other types of processes to consider during process creation are
subprocess and detached process:
- A subprocess becomes part of the same scheduling class as the
parent process, even though the subprocess might not match the criteria
of the class. That is, the subprocess's user and account name and/or
UIC might not be part of the class's record.
- A detached process joins the same scheduling class as the process
that creates it unless the detached process executes the LOGINOUT image
(LOGINOUT.EXE) during process creation. If a detached process executes
LOGINOUT, it joins a class if it matches the class criteria in the
class scheduler database.
Although a process can join a scheduling class at process creation
time, you can change or modify its scheduling class during runtime with
the SET PROCESS/SCHEDULING_CLASS command.
Determining If a Process is Class-Scheduled
You can determine whether a process is class-scheduled by any of the
following methods:
- Either of the following DCL commands:
$ SHOW SYSTEM/SCHEDULING_CLASS
$ SHOW SYSTEM/FULL
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For more information about the DCL command SHOW SYSTEM, see
HP OpenVMS DCL Dictionary: N--Z.
- The SYS$GETJPI system service, using the JPI$_SCHED_CLASS_NAME item
For more information about the SYS$GETJPI system service, see
HP OpenVMS System Services Reference Manual: A--GETUAI.
- The AUTHORIZE utility
When a new user is added to the SYSUAF
file, or when a user's record is modified, AUTHORIZE searches the class
scheduler database file to determine if this user is a member of a
scheduling class. If it is, then AUTHORIZE displays the following
message:
UAF-I-INCLASS, user belongs to at least 1 selecting class
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For more information about the AUTHORIZE utility, refer to that
chapter in this manual.
CLASS_SCHEDULE DELETE
The DELETE subcommand deletes a scheduling class from the class
scheduler database file.
Format
CLASS_SCHEDULE DELETE class_name
Parameter
class_name
Specifies the name of the scheduling class. You must specify a class
name with the DELETE command. The maximum length for this name is 16
characters.
Qualifiers
None.
CLASS_SCHEDULE MODIFY
The MODIFY subcommand changes the characteristics of a scheduling class.
Format
CLASS_SCHEDULE MODIFY class_name
Parameter
class_name
Specifies the name of the scheduling class. You must specify a class
name with the MODIFY command. The maximum length for this name is 16
characters.
Qualifiers
/ACCOUNT
Specifies which user is part of this scheduling class. This is part of
a user's SYSUAF record.
The syntax for this qualifier is as follows:
[/ACCOUNT = (name1, name2,...name"n")]
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/CPULIMIT
Defines the maximum amount of CPU time that this scheduling class can
receive for the specified days and hours. You must specify this
qualifier when adding a class.
The syntax for this qualifier is as follows:
/CPULIMIT = ([primary], [h1-h2=time%],[h1=time%],
[,...],[secondary],[h1-h2=time%],[h1=time%],[,...])
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The h1-h2=time% syntax allows you to specify a range of hours followed
by the maximum amount of CPU time (expressed as a percentage) to be
associated with this set of hours. The first set of hours after the
keyword PRIMARY specifies hours on primary days; the set of hours after
the keyword SECONDARY specifies hours on secondary days. The hours are
inclusive; if you class schedule a given hour, access extends to the
end of that hour.
/PRIMEDAYS
Allows you to define which days are primary days and which days are
secondary days.
The syntax for this qualifier is as follows:
[/PRIMEDAYS = ([no]day[,...])]
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You specify primary days as MON, TUE, WED, THU, FRI, SAT, and SUN. You
specify secondary days as NOMON, NOTUE, NOWED, NOTHU, NOFRI, NOSAT, and
NOSUN.
The default is MON through FRI and NOSAT and NOSUN. Any days omitted
from the list take their default value. You can use the DCL command,
SET DAY, to override the class definition of primary and secondary days.
/UIC
Specifies which users are part of this scheduling class. This is part
of a user's SYSUAF record.
The syntax for this qualifier is as follows:
[/UIC = (uic1,uic2,...uic"n")]
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/USERNAME
Specifies which user is part of this scheduling class. This is part of
a user's SYSUAF record.
The syntax for this qualifier is as follows:
[/USERNAME = (name1, name2,...name"n")]
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/WINDFALL
Specifies that all processes in the scheduling class are eligible for
windfall.
The syntax for this qualifier is as follows:
By enabling windfall, you allow processes in the scheduling class to
receive a "windfall," that is, a small percentage of CPU
time, when the class's allotted CPU time has been depleted and a CPU is
idle. Rather than let the CPU remain idle, you might decide that it is
better to let these processes execute, even if it means giving them
more than their alloted time.
The default value is for windfall to be disabled.
Description
To remove a time restriction, specify a zero (0) for the time
percentage associated with a particular range of hours.
To remove a name or uic value, you must specify a minus sign in front
of each name or value.
CLASS_SCHEDULE RESUME
The RESUME subcommand complements the suspend command. You use this
command to resume a scheduling class that is currently suspended.
Format
CLASS_SCHEDULE RESUME class_name
Parameter
class_name
Specifies the name of the scheduling class. You must specify a class
name with the RESUME command. The maximum length for this name is 16
characters.
Qualifiers
None.
CLASS_SCHEDULE SHOW
The SHOW subcommand displays the characteristics of a scheduling class.
Format
CLASS_SCHEDULE SHOW [class_name] [/qualifier]
Parameter
class_name
Specifies the name of the scheduling class. You must specify a class
name or the /ALL qualifier with the SHOW command. The maximum length
for the class name is 16 characters.
Qualifiers
/ALL
Displays all scheduling classes. The qualifier must be specified if no
class name is given.
/FULL
Displays all information about this scheduling class.
Description
By default, a limited display of data is shown by the SHOW subcommand.
The default displays the following:
- Name
- Maximum CPU time or times for each range of hours
- Primary days and secondary days
- Windfall settings
CLASS_SCHEDULE SUSPEND
The SUSPEND subcommand suspends the specified scheduling class.
Format
CLASS_SCHEDULE SUSPEND class_name
Parameter
class_name
Specifies the name of the scheduling class. You must specify a class
name with the SUSPEND command. The maximum length for this name is 16
characters.
Qualifiers
None.
Description
When you suspend a scheduling class, all processes that are part of the
scheduling class remain as part of the class but are granted unlimited
CPU time.
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