Cache type advantages and disadvantages

The following table summarizes the advantages and disadvantages of the various cache types. Whether a cache type and size are effective for you depends on your available resources and the activity on your system.

Related topic

Choosing-cache-types

Cache type

Advantages

Disadvantages

Best use

Fixed virtual storage

  • Fast access
  • No paging
  • Good compression performance
  • Extremely large caches (up to 511 GB on z/OS systems)


  • Most expensive resource: backed by real storage
  • Most likely to impact system performance
  • Practical only for small caches on non-z/OS systems


  • Small mission-critical tables under special circumstances
  • Use compression when effective


Pageable virtual storage

  • Fast (when backed by sufficient real storage)
  • Good compression performance
  • Extremely large caches (up to 511 GB on z/OS systems)


  • Pageable
  • Moderately expensive resource: must be backed by sufficient real and auxiliary storage
  • Can affect overall system performance


  • Use compression when effective
  • Small mission-critical tables on non-z/OS systems

Data space

  • Good compression performance
  • Large caches (up to 2 GB)
  • Moderately expensive resource: backed by real storage and auxiliary storage
  • Pageable
  • Can affect overall system performance
  • Compressed tables
  • Recommended for snapshot utilities object definition

ESO hiperspace

  • Expanded storage only
  • No paging
  • Less expensive resource
  • Large caches (up to 2 GB)
  • Pages can be stolen on busy systems
  • Not quite as effective as the other cache types for compression, but still effective.

Obsolete



 

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