This section contains commonly used words and phrases in this document.
Master volumeA physical disk device or volume that contains the original information for a particular application or suite of applications.
Shadow volumeA physical disk device or volume that contains the changed point-in-time data or full image of the original master volume.
BitmapA file, physical disk partition, or volume used by the Instant Image software to maintain the current state of the data between the master and shadow volumes.
Independent copyAn identical copy of the point-in-time master volume (that is, a copy of the master volume when the image was taken) that is stored on the shadow volume. After it is established, an independent Instant Image operation starts a block copy operation from the master volume to the shadow volume as a background process. While the copy is in progress, the Instant Image software treats accesses to the shadow volume as if the shadow volume is a dependent image. An independent copy can be exported to another Solaris Operating Environment (Solaris OE) server.
Dependent copyA point-in-time view of the master volume. After it is established, a dependent copy is immediately available to the backup application. The shadow volume maintains the original data from modified blocks on the master volume since the copy was established. All access to blocks not changed after the point-in-time copy is taken come directly from the master volume. The shadow volume is accessed only when the bitmap indicates that the master volume has been changed for the accessed data block. A compressed dependent copy has the advantage of not requiring a duplicate amount of storage. A dependent copy must remain within the server.
Volume PairA volume pair consists of the master volume and its related shadow volume. Each volume pair is supported by one bitmap. You can create as many volume pairs as necessary. The Instant Image software is limited only by the amount of available storage.