ADACOM Initialization Parameters

An unlimited number of Adabas nucleus clusters, each with up to 32 members sharing a common database, can be defined per parallel sysplex.

The ADACOM initialization task:

  • must be run on any operating system image that has cluster users but no cluster nuclei to set up the environment.

  • can optionally be used to monitor and control the nuclei of one or more sysplex clusters.

Parameters specify the SVC/DBID combinations (sets) that the ADACOM is to manage. The DBID identifies the external physical database shared by a particular cluster of nuclei and known to the application. The SVC value may vary within a cluster and the same SVC may be used for different clusters. Other ADACOM parameters are discussed in the following sections.

Although a single ADACOM job can run all SVC/DBID sets in a sysplex environment, it is possible to run multiple ADACOM tasks simultaneously with the same, mixed, or completely different SVC/DBID sets. A subtask is attached to the ADACOM task for each SVC/DBID set occurring in the input of ADACOM. All work pertaining to an SVC/DBID set is performed by the subtask.

The COMPRINT data set prints global messages that apply to all SVC/DBID sets defined to an ADACOM task. In addition, a SYSOUT data set is dynamically allocated for command output to each SVC/DBID set. The format of this data set DD-name is Pssddddd where ss is the last two digits of the SVC and ddddd is the DBID.

For a sample job to run ADACOM, see the section Create a Startup Procedure for ADACOM.

CMDMGR - ADACOM Use

Parameter Specify... Possible Values Default
CMDMGR whether ADACOM remains in use as a command manager after initialization or quiesces. YES | NO YES

The CMDMGR parameter specifies whether the ADACOM task remains in operation as a command manager for the cluster nuclei (CMDMGR=YES) or whether it runs like a batch job and terminates after processing the commands given in DDKARTE (CMDMGR=NO).

The ADACOM task used to allocate and monitor the PLXCB and subordinate data structures in common storage (ECSA) terminates after processing the commands given in DDKARTE, if CMDMGR=NO has been specified for all SVC/DBID pairs. If CMDMGR=YES (the default setting) has been specified for one or more SVC/DBID pairs, the ADACOM task stays active and accepts operator commands for displaying and controlling the multiprocessing environment.

DBID - Database Identification

Parameter Specify... Minimum Maximum Default
DBID the database to be used. 1 65000 none

The DBID parameter designates the ID of an Adabas cluster's external physical database; that is, the database number that the user programs address to send commands to the single physical database of an Adabas nucleus cluster.

This number must be unique among all Adabas database IDs, NUCIDs, Natural buffer pool IDs, Entire Net-Work target IDs (suggested range 65482-65535), and internal target IDs used by Adabas Cluster Services (restricted range 65001-65481).

FORCE - Force Restart after Abnormal Termination

Parameter Specify... Possible Values Default
FORCE whether ADACOM forces a restart after an abnormal termination. YES | NO NO

If Adabas believes there are still active nuclei, ADACOMs, or users on an image after a termination, an NU parameter value that is different from the NU value already in effect will not be recognized on restart. If you are certain that Adabas is wrong in its belief, you can use FORCE=YES to force a clean restart.

Note, however, that if a sysplex cluster nucleus or an ADACOM with the same SVC number is active on the image where FORCE=YES is used, it will crash.

Notes:

  1. FORCE=YES works only when the NU parameter value is being changed and has the effect of resetting the environment.
  2. The nucleus ADARUN parameter FORCE is neither seen nor used by the Adabas Cluster Services SVCCLU. The ADACOM parameter FORCE may only be used to change the NU that is valid for the cluster.
  3. If you use the ADACOM FORCE parameter, remember to remove it from ADACOM after you have reset the environment.

LOC - Specify PLXCB Location

Parameter Specify... Possible Values Default
LOC where to place the PLXCB structures that maintain information about nuclei and users. CSA | DSP CSA

To provide relief from 31-bit ECSA storage constraints you may direct the PLXCB be placed in a dataspace. This is available only under z/OS.

Notes:

  1. To use a PLXCB dataspace ADACOM must be started to define the dataspace before any nuclei start.
  2. ADACOM must remain active as long as any nuclei or database users on the local system are active.
  3. The dataspace is mapped into 31-bit private storage in the ADACOM and Adabas nucleus address spaces and requires virtual storage space there (less than 1 MB for every 10,000 configured users, as per the NU parameter).
  4. A mapped dataspace can be captured in SYSUDUMP.
  5. The dataspace is a common storage dataspace (i.e., allocated with SCOPE=COMMON). The number of dataspaces of this kind in one operating system image is limited by the MAXCAD parameter in SYS1.MACLIB(IEASYSxx), which can range from 10 through 250 and has a default value of 50.

NU - Number of User Table Elements

Parameter Specify... Minimum Maximum Default
NU the number of users that can be active in parallel on sysplex cluster nuclei in the local image. 20 16 777 215 200

In the extended CSA (ECSA), the SVCCLU maintains a user table with entries (UTEs) containing information about every active user in the sysplex cluster nuclei on the local image. A UTE is assigned when a user issues an OP command or (if the user did not issue an OP command) at the first Adabas command. The UTE is released when the user issues a CL command or when the assigned cluster nucleus otherwise deletes the user's UQE (e.g., due to timeout).

The ADACOM NU parameter specifies the number of concurrent users (UTEs) allowed for all cluster nuclei on the local operating system image. The first cluster nucleus or ADACOM started governs the value for NU: different values set for subsequent nuclei or ADACOMs are ignored.

To manually change the NU value, you must stop all sysplex cluster nuclei and ADACOM initialization tasks (if used) in the local image that have the same SVC number, modify the NU value for all the nucleus and ADACOM jobs, and then restart.

When the NU parameter is set to zero, any space allocated for the user table is freed, the Adabas Cluster Services control block (PLXCB) is freed, and the ADACOM subtask for this SVC/DBID set terminates, regardless of the CMDMGR parameter setting. However, if the ADACOM subtask believes that there are active nuclei or users on this database, and FORCE=YES is not used, no action is taken and the subtask terminates abnormally with user ABEND 40 (hex). The ADACOM main task and any subtasks handling other SVC/DBID sets are not affected.

Example:

Run the Adabas cluster nuclei on the local image with 500 elements in the user table. 

NU=500

SVC - Interregion Communication Number

Parameter Specify... Possible Values Default
SVC the supervisor call number to be used for the Adabas Cluster Services session. 200-255 249

The SVC is used to perform various Adabas internal functions; the number is used to communicate between the users and the database.

The SVC number is specified as an integer and must correspond to the number used for the version 8.2 Adabas SVC (ADASVC). Valid SVC values are 200-255.

Example:

Execute an Adabas Cluster Services session under an OS/390 or z/OS image using SVC 202. 

SVC=202