Data Compression Program for VM/ESA
Description of Data Compression Program for VM/ESAHighlights of VM Data Compression
Major Advantages of VM Data Compression
Business Value of VM Data Compression
System Considerations for VM Data Compression
Description of Data Compression Program for VM/ESA
VM Data Compression Program (PID # 5697-235)Data compression has long been recognized as an effective technique to reduce data storage requirements and to reduce the load on the I/O subsystem. While compression products have long been avialable for various operationg environments and data types, compression for CMS minidisk file data has never been supported, until now. With the availablility of DATA COMPRESSION PROGRAM for VM/ESA, data compression is now supported for CMS minidisks.
DATA COMPRESSION PROGRAM for VM/ESA enables VM customers to automatially and transparently compress and expand CMS minidisk file data. This capability can help reduce DASD utilization, load on the I/O subsystem, and staff time spent managing minidisk space and "disk full" conditions.
VM DATA COMPRESSION PROGRAM performs compression and expansion dynamically as files are being created and updated or read by application programs. Because data compression is automatic and Because data compression is automatic and transparent, no modifications are required to application programs.
Data compression is controlled throught the use of compression rules stored in a rules database managed by a rules server virtual machine. Compression activity is reported in compression statistics records stored in a statistics database managed by a statistics server virtual machine.
Highlights of VM Data Compression
- Reduces DASD requirements for CMS minidisk files
- Provides automatic, transparent compression and expansion of data in CMS minidisk files.
- Reduces system I/O load and improves storage utilization for CMS minidisk caching.
- Exploits the S/390 hardware compression facility
- Allows system administrators and CMS users to specify criteria to control data compresssion.
- Provides five compression techniques, including a dynamic data analyzer that selects the compression technique that yields the best compression performance
- Includes a Trial Utility program and a Compression Simulation mode which allows system administrators to evaluate the benefits of data compression without actually writing compressed data in CMS files
- Requires no changes to application programs
Major Advantages of VM Data Compression
- Compression and expansion of minidisk files is automatic and transparent, requiring no application modifications.
- Compressed files occupy fewer blocks of disk space and may require fewer I/O's to read, reducing access time and load on the I/O subsystem.
- Provides commands which allow system administrators and general users to control data compression at the CMS file level.
- Provides commands which allow system administrators and general users to view statistics on data compression to determine compression benefits.
- Provides five compression algorithms, allowing the installation to choose the method which produces the best results with the least consumption of system resources.
- Exploits the S/390 hardware assisted compression feature on ES/9000 series processors (if available).
Business Value of VM Data Compression
- Reduces DASD costs
- Improves data access time, improving productivity
- Saves time spent managing minidisk space allocations
System Considerations for VM Data Compression
Software
The following minimum version or release levels are required for installing DATA COMPRESSION PROGRAM for VM/ESA. Follow-on versions or releases of these products can be used unless otherwise stated.Required software
Optional software
DATA COMPRESSION PROGRAM for VM/ESA is written in Assembler and compiled REXX. IBM Library for SAA REXX/370 Release 2 (or later) is required to take advantage of the performance benefits of compiled REXX. The Alternate Library for SAA REXX/370 is distributed with the product for customers who cannot take advantage of compiled REXX programs.