Creating VSAM caching service datasets

Zowe can work in a high availability (HA) configuration where multiple instances of the Zowe launcher are started, either on the same LPAR or different LPARs connected through sysplex distributor. If you are only running a single Zowe instance on a single LPAR you do not need to create a caching service so you may skip this step.

In an HA setup the different Zowe API Mediation Gateway servers share the same northbound port (by default 7554), and client traffic to this port is distributed between separate gateways that in turn dispatch their work to different services. When any of the services individually become unavailable the work can be routed to available services, which means that the initial northbound request will be fulfilled.

There are different storage methods that can be used as as the caching service for Zowe. One of these is VSAM and this chapter describes how to create the data sets if you are using VSAM as your caching service. If you are using another caching service such as redis or infinispan then you do not need to create any VSAM files and you can skip the step described in this chapter. For more information on the different caching services see Configuring the Caching Service for HA.

Using zwe init vsam command

The command zwe init vsam uses the template JCL in SZWESAMP(ZWECSVSM). You can edit and submit this yourself, or else if use zwe init vsam which will copy the source template member from zowe.setup.mvs.hlq.SZWESAMP(ZWECVCSM) and create a target JCL member in zowe.setup.mvs.jcllib(ZWECVSCM) with values extracted from the zowe.yaml file.

zowe:
  setup:
    mvs:
      hlq: IBMUSER.ZWE
      jcllib: IBMUSER.ZWE.CUST.JCLLIB
    vsam:
      mode: NONRLS
      volume: VOL123
      storageClass:
  components:
    caching-service:
      storage:
        mode: VSAM
        vsam:
          name: IBMUSER.ZWE.CUST.CACHE

• zowe.components.caching-service.storage.vsam.name variable

  This is the data set name that the ZWECSVSM JCL will create. This is used to replace all occurrences of #dsname in the ZWECSVSM data set.

  Note: The ZWECSVSM JCL defines the key length and record length of the VSAM instance. If the key length and record length of this JCL is changed, zowe.environments.CACHING_STORAGE_VSAM_KEYLENGTH and zowe.environments.CACHING_STORAGE_VSAM_RECORDLENGTH must be set to the new values.

• zowe.components.caching-service.storage.mode variable

  This specifies whether you would like to use Record Level Sharing (RLS) for your VSAM data set. RLS is recommended for Sysplex deployment. NONRLS is also an allowed value.

• zowe.setup.vsam.storageClass variable

  If you use the RLS mode, a storage class is required.

• zowe.setup.vsam.volume variable

  If you set to use the NONRLS mode, a storage volume is required.

If you want to preview the member before submitting it use the value --security-dry-run, otherwise the command will submit the JCL and wait for its completion.

>zwe init vsam -c ./zowe.yaml
-------------------------------------------------------------------------------
>> Create VSAM storage for Zowe Caching Service
Modify ZWECSVSM
- IBMUSER.ZWE.CUST.JCLLIB(ZWECSVSM) is prepared
Submit USER.ZWEV2.CUST.JCLLIB(ZWECSVSM)
- Job ZWECSVSM(JOB05407) ends with code 0 (COMPLETED).
>> Zowe Caching Service VSAM storage is created successfully.
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