IAM is a transparent alternative to VSAM KSDS, ESDS and RRDS files, and (as an additional cost option) for Alternate Index (AIX) files.
IAM relieves VSAM performance and bottleneck issues, and eases VSAM tuning problems. It can shorten job elapsed times, reduce I/Os and cut CPU consumption compared to VSAM.
IAM's Real Time Tuning mechanism monitors I/O activity and dynamically changes the number of data buffers, and eliminates entirely the I/O to the index. The optional data compression can further reduce disk space requirements compared to VSAM without the usual overhead associated with data compression. A compressed IAM file typically uses less CPU than its uncompressed VSAM equivalent, and it also uses less CPU than other 3rd party VSAM compression alternatives.
Here are the typical performance expectations when converting a VSAM file to IAM -
- 20-80% reduction in VSAM batch elapsed times
- 40-80% reduction VSAM I/Os
- 20-70% reduction VSAM CPU utilization
- 30-70% reduction in VSAM DASD space requirements
- 20-80% reduction in VSAM online response times
These savings with IAM can be achieved in a very short space of time, allowing you to quickly and easily reduce the amount of time spent on VSAM-related capacity planning, batch tuning, and performance monitoring. IAM does not require any modifications to the z/OS operating system and is designed to coexist with VSAM. Typically, IAM can be installed and operational in less than 1 hour.
3rd Party VSAM Applications
Many of the popular z/OS application packages make extensive use of VSAM files, and a large number of these files have been successfully converted from VSAM to IAM. Some 3rd Party Vendor Packages that IAM customers have successfully converted from VSAM to IAM include Banking, Human Resources, Hospital, Report Distribution, Insurance, Payroll, Account Receivables and Payables.
Record-Level Sharing (IAM/PLEX)
IAM provides several options for Record-Level Sharing. IAM/RLS is included in the base license and provides Record-Level Sharing for a single system, which allows an IAM file to be concurrently accessed by two or more applications running in the same LPAR. IAM/PLEX is an additional cost option, and it provides Record-Level Sharing for IAM data sets across multiple z/OS systems and LPARS that are connected as a z/OS SYSPLEX.