zPET - IBM Z and z/OS Platform Evaluation and Test - Group home

RLS Catalog Migration

By Lora Milczewski posted Wed March 25, 2020 12:09 PM

  

RLS Catalog Migration

Introduction

 

RLS for Catalog is an enhancement to the Integrated Catalog Facility (ICF) to exploit VSAM Record Level Sharing (RLS) and Transactional VSAM (TVS).  The purpose of this enhancement is to improve performance, stability, usability, and availability for catalogs.  Below, we introduce an example of migrating a user  catalog to RLS mode. We will use catalog CATALOG.DSNDBCG as an example.

Migration Steps

1. Make sure all the systems sharing the user catalog are running on z/OS V2R1. The ‘D IPLINFO’ will show the z/OS release info. 

If the catalog is open on a pre-z/OS 2.1 system, then trying to enable RLS mode will result in a message like: IEC353I SERVICE 'CLRC' RETURNED RC-236-030, QUIESOFF, RCAT.RLSTEST

 

2.  The RLS enabled catalog must be SMS-managed. Check the status of the catalog using the LISTCAT command.

 

image

Here, CATALOG.DSNDBCG is already SMS-managed. If the catalog is not SMS managed, then you should define new constructs and update the SMS ACS routine for catalogs. Then run EXPORT/IMPORT to reorg catalog and ensure that it gets allocated onto a SMS managed volume.

 

3. Make sure that the Storage Class for catalog contains Cache Set Name for it. Here, CATRLS is a SC for RLS catalog and RLSSETX1 is a cache set for it.

image

 

4. Lock the catalog before taking any action.

 

5. Alter catalog to add LOG(NONE) parameter.

 

image

 

After the ALTER job finished successfully, LISTCAT will show following.

 

image

 

6. Unlock the catalog.

 

7. To enable RLS processing for the catalog either ALTER the catalog to add RLSENABLE attribute, or issue ‘F CATALOG,RLSENABLE(CATALOG.DSNDBCG)’.  Here we use the commands.

 

image

 

8. Monitor performance of that catalog and associated VSAM/RLS objects. Here we use the ‘F CATALOG,ALLOCATED’ command to check the status of the catalog.

 

image

 

Here ‘U’ indicates that the catalog is RLS enabled.

 

Also use LISTCAT to check the RLS attribute.

 

image

 

9. Run EXAMINE, DIAGNOSE to make sure catalog is good.

 

Summary

RLS for Catalog is an important feature in z/OS V2R1. It’ll improve the performance of busy catalogs. If there is any busy catalogs in your systems, you can try to migrate it to the RLS model and monitor the performance by using modify catalog commands or RMF.