Purpose of the ACC/SRS rules
Allocation Control Center and Space Recovery System are powerful, flexible systems software products that can control datasets as they are created, extended, and used in modern enterprise systems environments, including OS/390 and z/OS, as well as in Hitachi and Fujitsu systems. Allocation Control Center (ACC) provides a means to examine, test, and if necessary, dynamically alter many of the parameters that define how and where datasets are created and used, without the need to modify JCL, IDCAMS control statements, or SMS constructs. Space Recovery System (SRS) uses sophisticated processing techniques to effectively eliminate all out-of-space conditions that would otherwise occur in a large-systems environment, whether the cause is incorrect or obsolete size estimates, job scheduling conflicts, end-of-period processing load, or other, unpredictable types of failures. ACC and SRS are designed to meet the need for centralized, systemwide policies that are easily understood, enforced, and maintained. The DIF (Dynamic Install Facility) Rules Language is the key to the power and flexibility of ACC and SRS. DIF provides a common rules syntax and architecture across all of the SyncsortTM Storage Management products. ACC and SRS run under control of DIF, which provides all of the services ACC and SRS need to accomplish their tasks. DIF commands allow the ACC / SRS administrator to start, stop, and modify product operation, including which rules are to be used.
Purpose of this guide
This guide provides an overview of how the ACC/SRS rules are used, along with an example system which uses ACC and SRS for standards enforcement, dataset management, and out-of-space error prevention. The example system shows only some of the most common uses of ACC and SRS. Many more powerful capabilities, along with detailed explanations of the DIF rules language syntax, are described in the Dynamic Install Facility User’s Guide and the Allocation Control Center / Space Recovery System User’s Guide. Both of these documents, along with product load libraries and maintenance fixes, can be obtained from the Precisely Help Center.
Location of the ACC/SRS rules
ACC and SRS may use a single, common set of rules, or both products may use different rules. The rules consist of a series of statements in 80-character records, which must be contained in a partitioned dataset member. The partitioned dataset must be named in the //PARMLIB DD statement of the DIF catalogued procedure.
How ACC / SRS rules are activated
Activating rules at product START
When a MODIFY DIF,START command is issued in order to instruct DIF to start ACC or SRS, the appropriate member of the PARMLIB dataset is read and the rules are dynamically compiled and loaded into common storage for use by ACC or SRS. If a rule name (the name of a PDS member) is specified on the START statement, that member is used. If no rule name is specified, then a default name is used. For ACC and SRS, the default name is ACCRULES. START commands are normally placed in the STARTxx member of the DIF PARMLIB dataset so that they are executed automatically when DIF starts. An example of the START command is shown below. In this example, the member MYRULES in the PARMLIB dataset is used, rather than the default of ACCRULES.
F DIF,START ACC MYRULESREFRESHing Rules
The REFRESH command may be issued to DIF in order to activate a new set of rules or to activate an existing set of rules which has been updated. The REFRESH command may specify the product name (ACC or SRS) and the rule name (the PDS member to be used). If no rule name is specified, then the name used is the name of the rule set that is currently in use. Note that this differs from the case where no rule name is specified on the START command. In that case, the default rule name (ACCRULES) is used. For the REFRESH command, however, omitting the rule name indicates that the existing rules are to be reread from the PARMLIB dataset and the updated copy used. An example of the REFRESH command is shown below. The rule name is specified so that there is no question about which member of the PARMLIB dataset should be used. The rule name specified may be the same as the name of the rules currently in use.
F DIF,REFRESH SRS SRSRULESWhat Rules are Active Now?
The STATUS command instructs DIF to display which products are currently active, what release of each product is running, and what rule member is currently in use. The date and time at which the rule member was activated are also shown. For ACC and SRS, this date and time may be the most recent time at which a disk or tape device was varied online. This occurs because ACC and SRS rules are automatically REFRESHed whenever a device is varied online in order to update the pool definitions. The figure below shows an example of a STATUS command and the resulting output:
F DIF,STATUS
DIF01180-I PRODUCT VERSION STATUS RULES NAME DATE TIME
DIF01181-I SRS 5.1.13 ACTIVE SRSRULES 08/23/11 11:25
DIF01182-I SRSVSAM OPTION ACTIVE
DIF01181-I ACC 5.1.13 ACTIVE ACCRULES 08/23/11 11:26
DIF01182-I ACCVSAM OPTION ACTIVE
DIF01181-I DIF 5.1.14 ACTIVE
It is often useful to know what the contents of the rule member(s) were at the time ACC / SRS was started or when the rules were last REFRESHed. This can be accomplished via a SET command. If the following command is issued to DIF:
F DIF,SET productname RULELIST ONthen the contents of the rule member will be written to the SYSPRINT dataset allocated to the DIF started task when the product is activated or when the rules are next REFRESHed. The ‘productname’ above may be either ACC or SRS, or may be ‘*’ for all products. The SET command should be placed in the STARTxx member of the DIF PARMLIB dataset, so that it is executed automatically whenever DIF starts.