What does IMS Buffer Pool Analyzer do?

IMS Buffer Pool Analyzer provides more information than just IMS database buffer pool hit ratios and I/O rates. It provides a way to determine the impact of buffer pool changes before they are made.

Product features

IMS Buffer Pool Analyzer provides the following features:
  • Reviews your buffer pool environment and recommends changes to the number of buffers in each subpool to improve performance. Specific recommendations are made for the number of buffers for each subpool, and the resulting change in storage usage and reduction in number of database reads.
  • Provides information about the efficiency of OSAM cached buffers in a coupling facility (CF), and shows the effect of changing the amount of storage allocated to OSAM buffers in the CF cache structure.
  • Reviews the databases that are allocated to each subpool and document subpools that include databases with I/O access ratios that are inconsistent, providing the information that you can use to change your subpool configuration.
  • Identifies storage that is wasted because the most efficient buffer sizes are not available for database data sets.
  • Determines if adding or subtracting buffers will improve the performance of a selected buffer pool.
  • Models buffer pool usage to determine I/O rates for various numbers of buffers in each pool.
  • Identifies the databases that most heavily use each of the database subpools.
  • Performs scenario analysis, including analyzing the impact of creating new buffer pools or changing the block size of a database.
  • Reports on IMS OSAM, VSAM, and DEDB lookaside buffer pools, and IMS OSAM buffers that are cached in a coupling facility structure. The reports provide information that is required to make informed decisions about implementing changes to the structure and sizes of your database buffer pools and the information that should be used with the tuning methods that are also described in this document.
  • Requires no changes to any IMS control region or batch job during IMS Buffer Pool Analyzer installation. IMS can continue running while you are implementing the product. IMS Buffer Pool Analyzer dynamically accesses IMS data sets and control blocks from the trace address space to prepare to gather the information that is required to produce buffer pool reports.
  • IMS Buffer Pool Analyzer works under an IMS dynamic database buffer pools environment with several restrictions. For details, see How to gather data.

Product benefits

IMS Buffer Pool Analyzer provides the following benefits:
  • Eliminates guesswork when making changes to your buffer pool configuration so that you can understand the impact of changes to your system before you implement them.
  • Reduces IMS outages that are needed to make changes to your buffer pool configuration and achieve your buffer pool tuning objectives without having to try one change, and then another, and so on.
  • Reduces IMS real storage and virtual storage usage without the fear of severe impact on IMS performance and user response time. You can use IMS Buffer Pool Analyzer to model changes and see what the impact of subpool storage reductions will be before you implement changes.
  • Determines which buffer subpools have the most space for additional storage and hence, will result in the highest reduction in I/O rate when the subpool is increased in size.
  • Makes changes in your buffer pool configuration by adding and removing subpools or changing databases that are using subpools by understanding what the impact of the change will be on your system. IMS Buffer Pool Analyzer allows you to model different buffer pool configurations and see what the effect is on overall system performance.
  • Balances your IMS subpools to improve individual database data set hit ratios. IMS Buffer Pool Analyzer identifies database data sets with much higher or lower hit ratios than other database data sets in each subpool. You can use this information to create new subpools that include database data sets that are more similar in access patterns and improve overall buffer pool performance.
  • When making changes to your database access method or block size or CI size, you can model the changes and understand the impact of database changes on your buffer pool configuration. You can have IMS Buffer Pool Analyzer make recommendations on changes to your buffer pool configurations to accommodate the changes that are being made to your database data sets.
  • Includes OSAM coupling facility caching information to allow you analysis of the benefit of caching OSAM buffers in a coupling facility.
  • Provides support for IMS Tools Knowledge Base to store and retrieve IMS Buffer Pool Analyzer reports.
  • Supports IMS-managed ACBs. In an IMS-managed ACBs environment, IMS can manage the runtime application control blocks (ACBs) for databases and program views for you. When IMS manages ACBs, IMS no longer requires DBD, PSB, and ACB libraries. In an IMS-managed ACBs environment, IMS Buffer Pool Analyzer can obtain ACB information from the IMS directory instead of from ACB libraries.