Configuring the Caching Service for HA

Zowe uses the Caching Service to centralize the state data persistent in high availability (HA) mode. The Caching Service supports three storage methods: inMemory, VSAM and redis.

• inMemory

  This storage method is designed for quick start of the service and should be used only for single instance scenario and development or test purpose. Do not use it in production or high availability scenario.

  To use this method, leave the ZWE_CACHING_SERVICE_PERSISTENT configuration blank in the instance.env configuration file. When this method is enabled, the Caching Service will not persist any data. Also, if you have multiple instances of Caching Service, the data will not be shared across these instances.

• VSAM

  Note: Performance issues related to the VSAM data set have been observed, so it is recommended that you use this storage method for light workload. If heavy workload is expected on Zowe components, it is recommended that you use the redis storage method instead.

  Follow these steps oo use this method:

  1. Set the value of ZWE_CACHING_SERVICE_PERSISTENT to VSAM in the instance.env configuration file.
  2. Create a VSAM data set. See Creating a VSAM data set for instructions.
  3. In instance.env, configure ZWE_CACHING_SERVICE_VSAM_DATASET with the VSAM data set you created.

• redis

  To enable this method, set the value of ZWE_CACHING_SERVICE_PERSISTENT to redis in the instance.env configuration file. See Redis configuration for more information. To learn more about Caching Service, see Using the Caching Service.

If you are using zowe.yaml configuration other than instance.env, please check Configure component caching-service for configuration details.

Creating a VSAM data set

You can use the ZWECSVSM JCL to create a VSAM data set and define required security configurations. The ZWECSVSM JCL is provided as part of the PDS sample library SZWESAMP that is delivered with Zowe.

Before you submit the ZWECSVSM JCL, you must customize it and review it with a system programmer who is familiar with z/OS VSAM data set and storage.

The following variables are available in the JCL:

• #dsname

  This variable specifies the data set name that the ZWECSVSM JCL will create. Replace all occurrences of #dsname with the data set name that you want to specify. This data set name is the value for ZWE_CACHING_SERVICE_VSAM_DATASET in instance.env.

• MODE

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

  //         SET MODE=NONRLS                       RLS or NONRLS                  

• #storclas

  If you use the RLS mode, a storage class is required. Replace #storclas with your desired storage class name.

• #volume

  If you set to use the NONRLS mode, a storage volume is required. Replace #volume with you desired storage volume.

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, CACHING_STORAGE_VSAM_KEYLENGTH and CACHING_STORAGE_VSAM_RECORDLENGTH must be set in instance.env to the new values.

Follow these steps:

1. Customize the ZWECSVSM JCL. Edit the variables at the beginning and in the middle of the JCL.

2. Submit the ZWECSVSM JCL to create a VSAM data set.