Glossary

atomic

(adj.) Term used to indicate that a number of actions occur simultaneously. For instance, actions taken on grouped shadow volume sets occur at the same time, or atomically.

bitmap volume

(n.) For every 32 Kbyte block of a master volume that is part of a shadow volume set, a bitmap volume maintains a bit that indicates if the data at the block has changed with respect to its associated point-in-time copy.

changed

(adj.) Term applied to data blocks whose contents have been altered since the last synchronization.

compact dependent shadow volume

(n.) A shadow volume that is smaller than its associated master volume. Compact conveys that less storage is allocated, not that the data in the blocks is compacted or compressed in any way.

data service

Highly Available (HA) applications within the Sun Cluster environment are known as data services. The term data service is used to describe a third-party application that has been configured to run on a cluster rather than on a single server. A data service includes the application software and Sun Cluster software that starts, stops, and monitors the application. This terminology should not be confused with the concept of the Availability Suite software data service called Point-in-Time Copy.

delay variable

(n.) Part of the iiadm -P command. This variable sets the number of system clock ticks to wait before sending the next units variable set of data chunks.

dependent

(adj.) Describes a shadow volume set enabled as dependent, in which case no master volume to shadow volume copy is performed. After the shadow volume set has been enabled, the shadow volume cannot stand alone. It is dependent on the master volume to service read operations.

enable

(v.) In the Sun StorageTek Availability Suite 4.0 Point-in-Time Copy software, to use the enable command to associate the constituent volumes of a shadow volume set with one another.

export

(v.) With Point-in-Time Copy software, to make a shadow volume available for another host to use.

exportable shadow

A point-in-Time Copy set's shadow volume, in a Sun Cluster OE, that is in a different device group than the set's master and bitmap volumes. The ability to create a set with this configuration is available only when using the iiadm -n option, when initially creating the Point-in-Time volume set.

fast synchronization

See update.

full volume copy

(v.) To copy the full contents of the master volume to the shadow volume or the shadow volume's full contents to the master volume.

hot-backup

(n.) Mode of operation available with some database applications wherein there is no need to quiesce a shadow volume set prior to a point-in-time copy.

import

(v.) To move a shadow volume that has been exported by another host into a new host for the host's own use. The original host maintains the shadow volume set relationship for later joining of the shadow volume to its original shadow volume set. The importing host must maintain a record of changes to the imported shadow in a bitmap.

independent

(adj.) A shadow volume set can be enabled as independent, in which case a full volume copy is performed, master volume to shadow volume. After the copy, the shadow volume can stand alone, or independently.

join

(v.) To attach a shadow volume that has been exported to its original shadow volume set by using the join command.

master volume

(n.) The volume containing the original data.

overflow volume

(n.) A volume that is attached to a compact dependent shadow volume to accept write operations that are in excess of the compact dependent shadow volume's capacity.

point-in-time copy

(n.) A view of a data volume's contents relative to a point in time. While the data volume itself might continue changing with time, the point-in-time copy does not.

remote mirror

(n.) Software that provides for remote replication of data volumes over many line protocols, including TCP/IP. Remote Mirror software is part of Sun StorageTek Availability Suite software.

resynchronize

(v.) To perform synchronization between volumes in a shadow volume set that have been previously synchronized. This can be a full volume copy or an update.

scoreboard

(n.) Another name for bitmap volume.

scoreboarding

(v.) A technique that occurs when the Point-in-Time Copy software uses a bitmap volume to create point-in-time copies. For every 32 Kbyte block of a master volume that is part of a shadow volume set, a bit is maintained that indicates if the data at the block has changed with respect to its associated point-in-time copy.

shadow volume

(n.) A volume containing a point-in-time copy of the data on an associated master volume.

shadow volume set

(n.) The minimum configuration of volumes for use by the Point-in-Time Copy software, consisting of a master volume, a shadow volume, and a bitmap volume. Optionally, a shadow volume set might include an overflow volume.

synchronize

(v.) To make the shadow volume and the master volume of a shadow volume set match one another. This can involve a full volume copy or only the clearing of a bitmap, depending on the type of shadow volume set.

unchanged

(adj.) Term applied to data blocks whose contents have not been altered since the last synchronization.

units variable

(n.) Part of the iiadm -P command. This variable sets the number of data chunks to send before pausing for delay variable time to allow other applications to share system resources.

update

(v.) A synchronization of the master volume and the shadow volume in which only blocks of data that have changed since the last synchronization are written. Also called a "fast synchronization".

virtual shadow

(n.) An application's view of the shadow volume in a dependent shadow volume set. Some blocks of data might reside on the master volume and some might reside on the shadow volume. To a reading or writing application, it appears as a single volume, a virtual shadow.