With the ability to define very large volume sizes on certain hardware, it is possible that all your target and DLIB libraries could fit on a single volume. If possible, use a large enough volume for your target libraries so that you will not need multiple SYSRES logical extension volumes. However, some SYSRES volume types, such as the 3390-3, are not big enough to hold all the target libraries for a z/OS® system, with the result that you have to move some data sets to SYSRES logical extension volumes (overflow volumes). This section describes considerations for placing data sets on specific volumes. These considerations try to minimize your migration actions, taking into account:

• Your ability to use a system (or subsystem) replacement
• Data set and system availability
• System performance
• System cloning and servicing techniques
• Sysplex/multisystem operations
• Your ability to exploit new technologies
• Sharing of data sets
• Backup and recovery
• Disaster recovery.