Overview

To use data set separation, you must create a data set separation profile and specify the name of the profile to the base configuration. During allocation, SMS attempts to separate the data sets listed in the profile.

A data set separation profile contains at least one data set separation group. Each data set separation group specifies whether separation is at the PCU or volume level, whether it is required or preferred, and includes a list of data set names to be separated from each other during allocation.

Restriction: You cannot use data set separation when allocating non-SMS-managed data sets or with any process that does not use SMS volume selection, such as a full-volume copy utility (for example PPRC).

Recommendation: Use data set separation only for a small set of mission-critical data for the following reasons:

When separation is at the PCU level, an existing data set might be allocated to one or more PCUs from which the current allocation is to be separated. In this case, SMS either rejects all volumes on the PCUs from the SMS volume preference list or places them at a less-preferred position. Volume rejection might drastically reduce the number of eligible volumes or result in allocation failures if SMS rejects all volumes.
The use of wildcard characters in the data set names that need to be separated from each other might drastically reduce the number of eligible volumes or result in allocation failure if SMS rejects all volumes.
Data set separation can affect system performance. See the performance concerns listed in Factors affecting code path length.

For information about specifying the name of the data set separation profile to the base configuration, see Specifying the DS separation profile.

The following table lists the topics that are contained in this section:

Topic
Syntax for creating a data set separation profile
Data set requirements for a data set separation profile
Creating multiple data set separation profiles
Using data set separation with generation data groups and striping
Environmental conditions affecting data set separation
Factors affecting code path length