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Backstore Tape Capacity and Usage

CA Vtape can use any mainframe class physical or virtual tape solution for Externalization. Network File Systems, Hierarchical File Systems, or zLinux File Systems can also be used.

Note: CA Vtape automatically excludes its own Virtual Devices from intercepting Externalization tape mount requests.

When creating two copies, a PRIMARY and a DUPLEX Externalization Tape, the copies do not have to be written to the same type or capacity tape.

Many sites find it advantageous to write the PRIMARY Externalization tape to a virtual tape product, 3490 physical tape, or lower density 3590 physical tape and the DUPLEX Externalization tape to a high-density 3590 physical tape for movement off-site.

When high density tape drives are defined for a group (devices running in 3590 mode or 3490 emulated mode), Externalization and Recycle will not span Virtual Volumes across tapes (create multivolume data sets). Instead, when a Virtual Volume does not fit on the current tape, the current tape is closed, a new tape mounted, and the copy is restarted. If a PRIMARY and DUPLEX copy are being written, the restart will occur for both because they are written at the same time; only the copy that ran out of space will use a new tape.

Because PRIMARY and DUPLEX support does not require that the same media type be used for the two copies, the out-of-space condition could occur on each copy at different times for the same Virtual Volume. This would cause the copy operation to be restarted twice for the same Virtual Volumes.