EAV significantly increases the addressable disk storage and provides constraint relief for z/OS environments that are approaching the four-digit device number limit.
EAV increases the amount of addressable DASD storage per volume beyond 65,520 cylinders by changing how tracks are addressed. This increase is accomplished with a new track address format within the Volume Table of Contents (VTOC), which is referred to as 28-bit cylinder track address and a new way to manage this extra space as multicylinder units.
The following EAV increases are available for recent z/OS releases:
- For z/OS 1.12, the largest supported EAV volume is 262,668 cylinders
- For z/OS 1.13, the largest supported EAV volume is 1,182,006 cylinders
With EAV, IBM implements an architecture that provides capacities of hundreds of terabytes (TB) for a single volume.
Is CA7 compatible with the Extended Addressability Volumes (EAV) feature?
For CA7 11.3:
the COMMDS, the 9 queue files and the checkpoint dataset can reside in an EAV volume but
cannot use the 64M line functionality.
For CA7 12.0:
the COMMDS, the checkpoint and the 2 work queue datasets can reside in an EAV volume but cannot use the 64M line functionality, so they can be allocated on EAV DASD devices below the 65,521 cylinder line. Any attempt to open one of the datasets mentioned above as 'included' with a cylinder number greater than 65,520 will be rejected by the z/OS Operating System.
Starting with Release 14.0, Datacom/DB, which is used by CA7 12.0, is fully compatible with EAV functionality. Anyway, it is strongly recommended to check in SupportOnline for any published PTF affecting this interface.