HP Volume Shadowing for OpenVMS |
Creating and Managing Shadow Sets with System... |
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Using $MOUNT to Create and Mount Shadow Sets
The call to the $MOUNT system service has the following format: SYS$MOUNT itmlst
Item List to Create and Mount a Shadow Set illustrates MACRO-32 statements that produce a $MOUNT system service item list to create and mount a shadow set.
The following list describes the elements in Item List to Create and Mount a Shadow Set:
| Notice that the virtual unit item descriptor occurs first. This item descriptor specifies DSA23 as the name of the virtual unit. See Creating a Shadow Set for the proper naming syntax for the virtual unit and shadow set members. |
| The virtual unit item descriptor is followed by two member-unit item descriptors. Because Volume Shadowing for OpenVMS automatically determines the type of operation (copy or merge) necessary before disks can join a shadow set, all of the devices are mounted with MNT$_SHAMEM item descriptors. These item descriptors specify that the physical devices, $4$DUA9 and $4$DUA5, are to join the shadow set represented by DSA23. |
| The member item descriptors are followed by an item descriptor that specifies MYVOLUME as the volume label for the shadow set. |
| The last item descriptor specifies DISK$MYVOLUME as the logical name for the shadow set. |
Later, if you want to add another device to the shadow set, you make another call to $MOUNT that specifies an item list that contains the name of the virtual unit and the name of the device you want to add to the shadow set. Item List to Add a Member to a Shadow Set shows how to add the physical device $4$DUA10: to the shadow set created in Item List to Create and Mount a Shadow Set.
$MOUNT Shadow Set Item Codes briefly describes the $MOUNT shadow set item codes and discusses how to construct a valid $MOUNT item list. For a complete description of the $MOUNT service and all its item codes, refer to the HP OpenVMS System Services Reference Manual.
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