HP OpenVMS Systems Documentation

Content starts here 7.2 Configurations
HP OpenVMS I/O User’s Reference Manual: OpenVMS Version 8.4 > Chapter 7 Shadow-Set Virtual Unit Driver

7.2 Configurations

HP Volume Shadowing for OpenVMS does not depend on specific hardware in order to operate. All shadowing functions can be performed on Alpha and Integrity server systems running the OpenVMS operating system. Shadow set members must have the same physical geometry (that is, the same number of identical logical blocks (LBNs)) and members can be located anywhere in an OpenVMS Cluster.

7.2.1 Supported Hardware

Volume shadowing requires a minimum of one Alpha or Integrity server computer and disk drives.

See the most recent Volume Shadowing for OpenVMS Software Product Descriptions (SPD 27.29.xx ) for additional information about hardware requirements.

7.2.2 Compatible Disk Drives and Volumes

Volume shadowing requires compatibility among the physical units (disk drives and volumes) that form a shadow set. For example:

  • Units must be Files-11 On-Disk Structure Level 2 (ODS-2 or ODS-5) data disks.

  • Units and controllers must conform to DSA and OpenVMS MSCP, or must be SCSI FC compliant.

  • Units should not have hardware write protection enabled. Hardware write protection stops the volume shadowing software from maintaining identical volumes. However, the shadow set virtual unit may be mounted software write-locked with the /NOWRITE qualifier to MOUNT.