How to estimate the size of the standalone dump disk
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Since z/VSE 6.2 we support the standalone dump on SCSI disks in addition to ECKD disks. More and more z/VSE users create the standalone dump on disk instead of tape.
Before you create a standalone dump on disk with the DOSVSDMP utility or the dialog. There is always the question about the size of the disk. The size is dependent on the virtual storage you are interested in. Besides the shared areas, there may be partitions, data spaces and memory objects. You can specify the priority of partitions, data spaces and memory objects with the OPTION statement. The virtual storage will be dumped until the standalone dump disk is full.
You can use the following information to estimate the size of the disk:
That is you need to add up the SVA, partition, data space and memory object sizes you want to have included into the standalone dump to get to the total size. For the first three files a dump space of 300 cylinder (500000 blocks) should be sufficient in many cases. If you have enough disk space available and you want to get all virtual storage included, you can use e.g. the MAP command to calculate the required virtual storage for your workload (VSIZE or VSIZE- AVAIL). Keep in mind that unreferenced pages of virtual storage do not claim dump space.
Please create a new standalone dump after z/VSE upgrades, major service upgrades or if there is a PTF that addresses the standalone dump.
You can find more information in the z/VSE Hints & Tips book. The download page is here.