CMAS links can fail if you have high priority jobs running
alongside your CICS regions. For example, if a MAS holding a lock
cannot be dispatched because of a priority conflict, the CMAS links
can fail.
In order for a CICS system to be managed by CICSPlex SM, you must:
...
//STEPLIB DD DSN=CICSTS31.CPSM.SEYUAUTH,DISP=SHR
//DFHRPL DD DSN=CICSTS31.CPSM.SEYULOAD,DISP=SHR
//EYUPARM DD DSN=(Any PO or PS data set with LRECL=80)
//EYUHISTA DD DSN=(Optional 1st history dataset)
//EYUHISTB DD DSN=(Optional 2nd history dataset)
//EYUHISTn DD DSN=(Optional nth history dataset)
...
When changing these DD statements in the startup JCL for a CICS system make sure that the:
This section applies to CICS Transaction Server for z/OS®, Version 3 Release 1 CICS systems with the CICS-DB2 attachment facility.
Special considerations apply when BAS is used to install a DB2® connection defined to CICSPlex SM via a DB2CDEF resource definition.
When BAS is used to define and then install a DB2 connection (via a DB2CDEF) the connection starts out in NOTCONNECTED status. You can then issue a CONNect command on the DB2CONN view against an installed connection, to cause the connection to the DB2 subsystem to be activated.
In a test environment, it might be acceptable to wait for the MAS to start and then install the BAS definition, and issue a CONNECT command against the resulting DB2CONN.
However, in a production system, you might want the connection to be automatically activated when the MAS starts up, as part of the PLT processing sequence, so that the DB2 subsystem can be accessed immediately by programs and users.
Specifying the CICS SIT parameter DB2CONN=YES does not by itself achieve this, because at the time this and other SIT parameters are processed, CICSPlex SM has not yet installed any DB2CDEF objects.
The way to activate a DB2 connection during CICS startup is as follows:
You cannot use BAS to define and install an MQSeries® connection before the CICSPlex SM environment has been initialized.
You should verify that the sequential data set or partitioned data set member identified by the CICS SYSIN statement includes the appropriate CICS system initialization table (SIT) parameters, as described in Table 23.
Parameter | Explanation |
---|---|
APPLID= | VTAM® application ID for this CICS system. Used as MAS name when NAME(value) is not specified as a CICSPlex SM system parameter. |
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CPSMCONN=LMAS | Initialize the region as a local MAS. |
DFLTUSER=userid | Specify the user identifier that is to be used for security checking when a user is not defined to the ESM. |
DSALIM= | Limit of DSA storage below 16MB. Should be set to at least 4MB. |
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GRPLIST= | Identify the name of the group list containing the CICSPlex SM group added to the CSD file for the MAS. (See Updating CSD files using DFHCSDUP (MVS MAS) for additional information.) |
ISC=YES | Code YES to include the CICS programs required for interregion and intersystem communications. |
MCT= | Monitoring control table. If you have CICS performance class monitoring active, then you must specify a value for this parameter. You can use 2$ (the default) or an existing table. (See Note below.) |
MN=ON | Activates CICS Monitor. (See Note below.) |
MNFREQ=001500 | Writes performance class data every
15 minutes.
Note:
Set only for local MAS. |
MNPER=ON | Tells CICS to monitor performance classes. (See Note below.) |
Note for MCT, MONITOR, MN, and MNPER parameters:
To
get all data available for the TASK and MLOCTRAN views, MCT must have
a value specified, CICS monitoring for performance classes
must be activated, and you must be collecting performance class data. If you do not want this data written to an SMF data set, you can suppress the monitor records. See the description of the SUPPRESSCMF parameter in CICSPlex SM system parameters. |
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CICSPlex SM rarely uses all 25 of these additional
tasks. If you are using the MXT value alone to control application
transactions, increasing this value can allow more application transactions
to run concurrently. To prevent this from occurring, you can define
a transaction class for the application and set the MAXACTIV task
value to limit the number of concurrent transactions. ![]() |
SEC=
{YES|NO} |
Indicate whether external security
checking is to be performed for this CICS system.
Specify:
Notes:
|
SECPRFX={YES | NO ![]() ![]() |
Specify whether the user ID is used as the prefix that is added to the beginning of all resource names to distinguish this CICS system from other CICS systems. |
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XCMD= {YES|name|NO} | Indicate whether EXEC CICS system commands are to be included in security checking. Specify YES or NO. For more information about CICSPlex SM transaction security requirements, see the CICS RACF Security Guide. |
XDB2= {No|name} | Indicate whether DB2 resources are to be included in security checking. Specify NO or name. |
XFCT= {YES|name|NO} | Indicate whether file control entries are to be included in security checking. Specify YES or NO. For more information about CICSPlex SM transaction security requirements, see the CICS RACF Security Guide. |
XPCT= {YES|name|NO} | Indicate whether EXEC-started transactions are to be included in security checking. Specify YES or NO. For more information about CICSPlex SM transaction security requirements, see the CICS RACF Security Guide. |
XPPT= {YES|name|NO} | Indicate whether program entries are to be included in security checking. Specify YES or NO. For more information about CICSPlex SM transaction security requirements, see the CICS RACF Security Guide. |
XUSER={YES|NO} | Indicates whether CICS is to perform surrogate user checks. If you specify YES, the CICS region userid must be defined as a surrogate of the userid that starts a MAS using the COLM or CORM transaction. |
CICSPlex SM provides the ability to save and view data for completed tasks, that is historical task data. When an active task completes, its data is stored in a historical data store. The data store is made up of a number of VSAM KSDS data sets. There must be a minimum of two data sets and a maximum of twenty six data sets.
Each MAS must have its own set of CICSPlex SM history data sets. The data sets must be allocated to the MAS region by means of DD cards in the JCL with DD names of the form EYUHISTx, where x is a character suffix taking values A through Z. Dynamic allocation is not supported. The datasets must be allocated with a disposition of OLD. The suffix letters must be used in ascending sequence and no letters should be omitted. For example, if four history data sets are required use DD names EYUHISTA, EYUHISTB, EYUHISTC, and EYUHISTD.
The CICSPlex SM history data sets must be defined with the REUSE keyword. Task history recording uses the least recently used data set, or when starting for the first time EYUHISTA. When EYUHISTA becomes full, it switches to use EYUHISTB and so on in sequence. Each full data set remains open with its data available until the history recorder has filled all data sets and needs to start reusing the data sets. At this time EYUHISTA is set closed, emptied, re-opened, and reused first, followed by EYUHISTB and so on in sequence. If a data set is reused its previous contents are destroyed.
Until the history recorder requires to empty a data set in order to reuse it, the historical task data is available for use. The data is maintained across CMAS and MAS restarts. The history data sets need not be defined as recoverable, as unit of work recoverability is not required. However, the CICSPlex SM history recorder facility does require files to be defined as non-recoverable to avoid unnecessary logging in the MAS region.
In addition, the history
data sets must not be defined to use VSAM compression. The CPSM history
function initializes the data sets in order to calculate how many
records fit in the data set, so that it can safely use sequential
writes to the data set, thereby reducing the I/O overhead. Use of
VSAM compression invalidates that calculation and cause data to be
lost when the data set becomes full and a data set switch is required.
CICSPlex SM provides a tuning aid in the form of a EYUPARM called HISTRECSMSG to determine the optimum size for history data sets. HISTRECSMSG can activate the periodic output of messages detailing how many thousand records have been written to the data set. There is one record for each completed task. Since CICS file control supports extended format KSDS data sets, large history data sets over 4GB in size can be defined. However when considering using very large data sets, take into account that when the CICSPlex SM history recorder reuses a data set by emptying it, a large amount of data is lost and not available for subsequent queries. An alternative approach to having a small number of very large data sets, is to spread the data over more data sets. For example, by having twenty five data sets each one capable of holding one hours worth of completed task data, at least one days worth of data can always be maintained. When the oldest data set is reused, only one hours worth of data is lost.
CICSPlex SM provides a sample job called EYUJHIST
in SEYUINST for defining and
initializing
two history data sets.