Asynchronous Mirroring provides a controller-level, firmware-based mechanism for data replication between a local site and a remote site. Replication is managed on a per-volume basis, allowing a storage administrator to associate a distinct remote mirrored volume with every primary volume on a given storage array.
For Asynchronous Mirroring, the local storage array and the remote storage array can run different versions of firmware. The minimum firmware version supported is SANtricity firmware version 7.84.
This table shows the maximum number of defined mirrors that can be defined for each controller model.
|Storage Array||Maximum Number of Defined Mirrors|
|EF560 controller-drive tray||Up to 128|
|E5600 controller-drive tray||Up to 128|
|EF550 controller-drive tray||Up to 128|
|E5500 controller-drive tray||Up to 128|
|E2700 controller-drive tray||Up to 32|
Asynchronous mirror groups allow you to manage the synchronization process as a set to create a crash-consistent data-set on the remote storage array. Point-in-time images are used on the primary volume and the secondary volume to batch the resynchronization process. (A data repository volume is required for each mirrored volume.)
When write operations are performed to the primary volume of an asynchronous mirrored pair, the modified data region of the primary volume is tracked. Periodically, the firmware creates a new point-in-time image of the primary volume and sends the changed data regions to the secondary volume. When data synchronization completes, the system uses the point-in-time images on the secondary volume to ensure that the data is maintained in a consistent state during subsequent synchronization operations to the secondary volume.