Hiperspace buffering parameters
To use Hiperspace buffering, you must specify one or two optional parameters on the VSRBF subpool definition statement.
- HSO|HSR
- Specifies the action IMS takes
if Hiperspace buffering
requested for a subpool is unavailable.
- HSO
- Hiperspace buffering is optional. IMS continues to run.
- HSR
- Hiperspace buffering is required. IMS terminates.
- HSn
- Specifies the number of Hiperspace buffers to build for a subpool. The number n is a 1- to 8-digit number.
Hiperspace parameters are valid only for buffer sizes of 4K or multiples of 4K. Specifying Hiperspace parameters on buffers smaller than 4K causes an error. To use Hiperspace buffering you might need to unload your database and then reload it into 4K or multiples of 4K CI sizes to accommodate Hiperspace requirements.
If you decide to leave intact databases with CI sizes of less than 4K, do not allocate any buffers less than 4K. The CIs that are less than 4K are placed in 4K or larger buffer pools. However, the CIs compete with VSAM data sets already there. This method might be expedient in the short term.
Related Reading: For more information about VSAM buffers, including Hiperspace buffers, see z/OS® DFSMS: Using Data Sets.