Logical and Consistency Group Overview

This topic provides background information on the role of logical groups and consistency groups in AGM.

Logical Groups

A logical group is a logical grouping of applications from one or more hosts used for ease of management to apply a common policy to all the group’s applications. Mount, clone, and restore operations are performed on the images of each application in the group individually. Although you apply an SLA against a logical group, management of the data capture is performed one-by-one to the individual applications and there is no association among the applications in the group.

 

Consistency Groups

A consistency group is a collection of discovered applications from the same host. You create a consistency group to back up application data of all member applications together to preserve consistency of data across the member applications. You apply a common policy to the members of a consistency group.

Note: Generic applications and VMs are not allowed in consistency groups. Oracle does not support consistency groups of multiple databases. However, a consistency group may include a single Oracle database with other applications.

 

The Actifio appliance guarantees a consistent application data capture that undergoes snapshotting at the same moment in time for:

Applications on the same host that reside on volumes that are all in-band virtual disks.
Windows applications on the same host, including SQL Server, Exchange, and SharePoint databases, and local Filesystems.

For all other configurations, a consistency group can be defined and an image of its member applications will run as one job on the host but snapshots of each application will be independent and not be from the same point in time.

When creating a snapshot of these applications, the Actifio appliance resolves all of the applications into a collection of volumes. If all of these volumes are in-band virtual disks, then the consistency group goes through snapshotting at the same moment in time. If any one of the volumes is not in-band, then the consistency group is backed up as out-of-band application, and the constituent applications are self-consistent, but not at the same point in time.

Note: In-Band management is not applicable to Actifio Sky appliances.

Logical and consistency groups are managed in the same way that applications are managed.

To manage a logical or consistency group, see Managing Logical Groups and Consistency Groups
To restore a logical or consistency group, see Mounting Images

See also:

Working With Logical Groups

Working with Consistency Groups