Dynamic LDSs are defined using a standard naming convention of prefix.VVE.Vvolser.MM.CACHE where prefix is a DSN prefix defined to CA Vtape during the Customization Process and volser is the Virtual VOLSER.
These LDSs are dynamically defined using customized parmlib attributes whenever a Virtual Volume scratch mount or a recall from tape is processed.
A Virtual Volume always resides in a single LDS. If the application MODs to a Virtual Volume, the LDS containing that Virtual Volume will take secondary extents and span to another DASD volume if required. Alternatively, the current Virtual Volume is kept and a scratch Virtual Volume is mounted, causing a new LDS to be defined. After the application data set is closed and the Virtual Volume is dismounted, any control areas (CAs) within the LDS that do not contain data will be freed.
The dynamic LDSs can vary from 12 MB in size up to the chosen Virtual Volume Size depending on the amount of application data written. The Virtual Volume Size chosen is used as a maximum size limit. When the chosen size is reached, the current Virtual Volume is kept and another scratch Virtual Volume is mounted, creating a multiple volume tape data set.
Dynamic LDSs support Virtual Volume Sizes of 400, 800, 2000, 4000, 8000, and 16000 MBs.
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