One-to-One Volume Copy Operations

Continuous Access Journal requires a one-to-one relationship between the logical volumes of the volume pairs. A volume can only be assigned to one journal group pair at a time.

NOTE: Continuous Access Journal does not support operations in which one primary data volume is copied to more than one secondary data volume, or more than one primary data volume is copied to one secondary data volume.

One-to-One Journal Group Operations

The Continuous Access Journal supported configuration for a journal group pair is a one-to-one relationship. This means one journal group in one P9000 or XP can only pair with one journal group in another P9000 or XP.

Journal Group Requirement

The journal groups require that each data volume pair be assigned to one and only one journal group.

Configuring Continuous Access Journal

One journal group can contain multiple journal volumes. Each of the journal volumes can have different volume sizes and different RAID configurations. Journal data will be stored sequentially and separately into each journal volume in the same journal group, and each of the journal volumes that are used equally.

Journal volumes in the same journal group can be of different capacity. A journal volume in primary subsystem and the corresponding restore journal volume can be of different capacity.

Registering Journal Volumes

Unlike the Continuous Access Asynchronous device group that only contains data volumes, a journal group includes data volumes as well as journal volumes. Journal volumes must be registered in a journal group before creating a data volume pair for the first time in the journal group.

Journal volumes are assigned to a specific journal group. Each journal group has it own ID. The journal volumes assigned to the specific journal group can be used to create one journal group pair.

One journal group (JID) on primary array and one journal group (JID) on secondary array are used to create a journal group pair. Be sure to register journal volumes to journal groups on both primary and secondary arrays. The number and capacity of the journal volumes for a specific journal group on a primary or secondary array depends on the business need and IT infrastructure. To register journal volumes in a journal group use the “HP StorageWorks P9000 or XP Remote Web Console”.

Journal volumes can be registered in a journal group or can be deleted from a Journal group. Journal volumes cannot be registered or deleted when data copying is performed (that is, when one or more data volume pairs exist).

The journal volumes can be deleted from a journal group in the following occasions:

•When the journal group does not contain data volumes (that is, before a data volume pair is created for the first time in the journal group, or after all data volume pairs are deleted).

•When all data volume pairs in the journal group are suspended.

If a path is defined from a host to a volume, do not register the volume as a journal volume and define paths from hosts to journal volumes. This means that hosts cannot read from and write to journal volumes.

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