Duplicate VOLSER (Volume Serial Number)
When you select Entire as the initial copy option, the URz initial copy operation copies the VOLSER of the primary data volume to the secondary data volume, and therefore the primary data volume and secondary data volume of the URz pair will have the same VOLSER. Since the host operating system does not allow duplicate VOLSERs, the host system administrator must take precautions to prevent system problems related to duplicate VOLSERs. For example, the URz secondary data volumes must be defined in the system generation so they do not come online automatically (see WARNING below).
WARNING: If the volumes which will become URz secondary data volumes are physically attached to the same system images as the production volumes which will become the URz primary data volumes, the following problems can occur:
When a URz pair is released, the old secondary data volume is usually offline. When a host system is IPL’d (initial program loaded), the operator will be offered both volumes and asked which volume should be left offline – the old duplicate volser message. This can be confusing and is prone to error. To avoid duplication of VOLSER,
1.Identify the volumes that will not be accessed by the host system.
2.Perform CHP OFF or some other operation to ensure that the volumes are inaccessible.
3.When performing IPL, you must perform LOAD CLEAR.
Volume Types
The following DKC and DKU emulation types can be used for the URz software.
Table 3-1 Supported Emulation Types
Emulation
Support type
DKC | All CU images that can be used with USP V |
|
|
DKU (Drive) | All mainframe volumes that can be used with USP V |
|
|
All DKC and DKU (drive) emulation types for USP V can be used for URz software. In URz, the emulation types of primary and secondary data volumes are indicated.
The following CU emulation types can be used for MCUs (primary storage systems) and RCUs (secondary storage systems):
The CU emulation type of an MCU can be different from the CU emulation type of the corresponding RCU.
Chapter 3 Preparing for Universal Replicator z/OS Operations |
