Setting up the Distributed Data Server for z/OS

Applications that want to access sysplex-wide performance data, can retrieve their input from a single data server on one system in the sysplex, which gathers the data distributed on all systems in the sysplex. Therefore, this is called the Distributed Data Server (DDS).

The DDS offers an HTTP API which can access short-term data from the Monitor III as well as long-term data from the Postprocessor. An application program can send an HTTP request for selected performance data to the DDS.

Note: Equivalent to the DDS component GPMSERVE, which gathers performance data from z/OS systems in a sysplex, RMF XP provides a second DDS component called GPM4CIM, which you can use to gather performance data from AIX®, Linux and Windows operating systems. For general and setup information about RMF XP refer to Cross platform monitoring with RMF XP. The z/OS RMF Programmer's Guide provides information on how to exploit the HTTP API of GPM4CIM if you want to submit requests for AIX, Linux and Windows performance data. The remaining information in the current topic is about GPMSERVE for z/OS only.

Exploiters of Monitor III performance data provided by the DDS are, among others, z/OS Capacity Provisioning, z/OSMF, or RMF PM. If you want to monitor systems in a sysplex, you must set up a Distributed Data Server (DDS) host session on the system in the sysplex with the highest RMF™ release. If you want to monitor several sysplexes, each one needs to have an active DDS.

To start the DDS, RMF provides the cataloged procedure stored in SYS1.PROCLIB(GPMSERVE):

//GPMSERVE PROC MEMBER=00
//STEP1    EXEC PGM=GPMDDSRV,REGION=128M,TIME=1440,
//         PARM='TRAP(ON)/&MEMBER'
…
//GPMPPJCL DD   DISP=SHR,DSN=SYS1.SERBPWSV(GPMPPJCL)
…

You can modify it according to your requirements.

Prerequisites for exploiting the Monitor III HTTP API

On those systems where you want to monitor short-term Monitor III data, you need to start the Monitor III gatherer with identical MINTIME and SYNC options (see Description of Monitor III data gatherer options).

Also make sure, that the following prerequisites are met on your z/OS host:

Unix System Services must be configured in full function mode.
TCP/IP under Unix System Services must be configured and fully initialized.

Prerequisites for exploiting the Postprocessor HTTP API

To get access to Postprocessor data provided by the DDS, the GPMSERVE started task points to a Postprocessor job called GPMPPJCL. A JCL template for this job is stored in SYS1.SERBPWSV(GPMPPJCL).

You must adapt or replace the GPMPPJCL member to suit your installation, ensuring that the DDS is able to run RMF Postprocessor jobs. If you do not want to request Postprocessor data with the DDS, you can omit the GPMPPJCL DD card from the GPMSERVE started task.

By default, the RMF Postprocessor retrieves data from all available intervals in the SMF buffer. You can modify the GPMPPJCL template to retrieve only SMF data from the most current interval by adding a job step similar to the following GETSMF sample job step:

//GETSMF EXEC PGM=ERBAPPL,PARM='?/*/70:78'
//SMFDATA DD DISP=(NEW,PASS),UNIT=SYSDA,SPACE=(CYL,(2,2))
//ERBLIST DD SYSOUT=*

The example job step retrieves SMF data from records 70 through 78 for the most current interval, indicated by the question mark used for the start time. If you use ERBAPPL in your GPMPPJCL job, you must add an MFPINPUT DD card to the Postprocessor job step RMFPP in GPMPPJCL with a backward reference to the SMFDATA DD card of the GETSMF job step, for example:

//MFPINPUT DD DISP=(OLD,PASS),DSN=*.GETSMF.SMFDATA

GPMPPJCL template

/*JOBPARM  SYSAFF=*
//RMFPP    EXEC PGM=ERBRMFPP
//MFPMSGDS DD   SYSOUT=*
//XPRPTS   DD   SYSOUT=*
//XPXSRPTS DD   SYSOUT=*
//XPOVWRPT DD   SYSOUT=*
//SYSOUT   DD   SYSOUT=*
//SYSIN    DD   *

Note that the Postprocessor API functionality is only available with JES2 installed. Omit the GPMPPJCL ddname in a JES3 environment.

The complete DDS HTTP API is described in the z/OS RMF Programmer's Guide.