START IRLMPROC
Format

.---------------------------------.
V |
>>-S irlmproc----+-----------------------------+-+-------------><
+-,DEADLOK='seconds#,cycles#'-+
+-,IRLMGRP=irlmds-------------+
+-,IRLMID=irlmid--------------+
+-,IRLMNM=irlmname------------+
+-,LOCKTAB=irlmlt1------------+
+-,MAXCSA=maxcsannn-----------+
+-,MAXUSRS=nnn----------------+
| .-NO--. |
+-,PC=-+-YES-+----------------+
| .-YES-. |
+-,PGPROT=-+-NO--+------------+
+-,SCOPE=-+-LOCAL----+--------+
| +-GLOBAL---+ |
| '-NODISCON-' |
| .-NO--. |
'-,TRACE=-+-YES-+-------------'
Usage
The START irlmproc command starts an IRLM component with
a procedure put in place by your installation. Symbolic parameters
in the procedure can be overridden using the START irlmproc command.
IRLM must be started before any IMS subsystem that needs the facilities
provided by IRLM.
The irlmproc identifies the procedure name of the IRLM to be
started.
Any IRLM parameter can be overridden using the START command.
- DEADLOK=
- Specifies the local deadlock-detection interval (in seconds),
and the number of local cycles that are to occur before a global
detection is initiated. You can specify the following:
- seconds#
-
This 1- to 4-digit numeric value, ranging from
1 to 9999, specifies the interval (in seconds) between IRLM local
deadlock-detection cycles. Although values above 5 are accepted,
the maximum used is 5.
Recommendation: Set this parameter to
be no greater than 5. This is because it takes multiple local cycles
to complete one global cycle. Otherwise, global deadlocks may not
be broken frequently enough to ensure maximum throughput.
- cycles#
-
This 1- to 4-digit numeric value, ranging from
1 to 9999, specifies the number of local deadlock cycles that must
expire before global deadlock-detection is performed. Although values
above 1 are accepted, the maximum used is 1.
Recommendation: Set this parameter
to be no greater than 5. This is because it takes multiple local
cycles to complete one global cycle. Otherwise, global deadlocks
may not be broken frequently enough to ensure maximum throughput.
- IRLMGRP=
- Specifies the name of the z/OS Cross-System Coupling Facility
(XCF) group for which this IRLM will serve as lock manager.
- irlmds
- The name of the XCF group.
- IRLMID=
- Specifies either a decimal number or a printable character
that is used to distinguish between multiple IRLMs. The IRLM with
the lowest ID value in the group becomes the global deadlock manager
for the group. You must specify a unique name for every IRLM in
the group. The total number of IRLMs that can be included in a group
is not related to the value you specify; the total number is limited
by your hardware, and may be lower than 255.
The irlmid can be either a one- to
three-digit number ranging in value from 1 to 255, or a printable
EBCDIC character. When you specify a character, you must surround
the character with enough single quotes to permit IRLM to understand that
this value is indeed a printable character. IRLM converts the character
to an EBCDIC value between 1 and 255.
Because of the way that z/OS interprets quotes, you must use
7 quotes on either side of the character.
Example: If you want to specify
the printable character 'D', you must specify IRLMID='''''''D'''''''.
- IRLMNM=
- Specifies the 1- to 4-byte z/OS subsystem name assigned to
this IRLM.
- LOCKTAB
- Specifies the lock table to be used by the data sharing group
specified in the GROUP parameter.
- irlmlt1
- Is the name of the lock table.
- MAXCSA=
- Specifies the maximum amount of CSA that IRLM is to use for
its lock structures. In displays, this storage is called accountable storage
because it is accountable to the value you set for MAXCSA. Use the
accountable storage high water mark (AHWM) data from messages DXR100I
and DXR121I to monitor IRLM's usage of common storage and as a basis
for adjustments to the MAXCSA value.
This parameter must be specified as a 1 or 3-digit number from
1 to 999. This number indicates the number of megabytes of CSA storage
that IRLM will use. If IRLM is using extended CSA support and running
on a z/OS system, this number indicates multiples of 1 MB of extended
CSA storage. For example, a specification of 3 states that IRLM
can use 3 MB of CSA, or 3 MB of ECSA, if IRLM is running with extended
CSA support on a z/OS system.
- MAXUSRS=
- Specifies the maximum number of users, from 2 to 248, that
can connect to the data sharing group.
- PC=
- Specifies whether a space switching program call is to be
used by IRLM. If PC=YES is specified, the IRLM lock control block
structure resides in the IRLM address space, and the space switching
program call (PC) instruction is used to obtain addressability to
the structure. If PC=NO is specified, the IRLM lock structure resides
in ECSA. The default for this parameter is PC=NO. Tells IRLM whether to place its COMMON STORAGE load modules into z/OS Page Protected Storage. PGPROT=YES is the DEFAULT and tells IRLM to place its COMMON Storage load modules into z/OS Page Protected Storage. If PGRPROT=NO is specified, IRLM will not place load modules in Page Protected Storage.
- SCOPE=
- Specifies whether the IRLM is to be used in a data-sharing
environment and, if so, whether the IRLM should automatically disconnect
when the associated IMS terminates.
- LOCAL
- Specifies that the IRLM is in a non-data-sharing environment
and there is no intersystem sharing.
- GLOBAL
- Specifies that the IRLM is in a data-sharing environment and
that intersystem sharing is to be performed. The IRLM disconnects
from the data-sharing group when there are no IMSs identified to
it. Both XCF and SLM are required
- NODISCON
- Specifies that the IRLM is in a data-sharing environment and
that intersystem sharing is to be performed. The IRLM remains connected
to the data-sharing group even when there are no IMSs identified
to it. Normal DISCONNECT from the sharing group does not occur.
You must explicitly stop the IRLM when NODISCON is specified. Both XCF and SLM are required.
With NODISCON, there is less impact on other systems when an IMS fails because z/OS is
not required to perform certain recovery actions that it normally
perform when an IRLM terminates. Another benefit of the NODISCON parameter is that IMS restarts more quickly after a normal
or abnormal termination because it does not have to wait for IRLM
to rejoin the IRLM data-sharing group.
- TRACE=
- Specifies whether the IRLM should trace activity during IRLM
startup. Traces are written to wrap-around trace buffers, that is,
the first buffer is reused after the last buffer is full.
- NO
- Do not initialize trace activity during IRLM startup. NO is the default.
To trace IRLM activity, use the TRACE CT command. See TRACE CT
- YES
- Initialize IRLM trace activity during startup.
Recommendation: Turn
on tracing in all data-sharing environments.

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