Global-Active Device allows volume consistent, remote, active-active replication.
When establishing a replication, the storage system copies all the data to the secondary volume. Depending on the volume size, the creation of the replica takes time. As with TrueCopy, you can optimize the process using DP volumes.
After creating the replication, the storage system maintains the replica on the secondary volume. The copy mechanism and data consistency is the same as for TrueCopy.
Unlike TrueCopy, read/write operations are permitted on both the primary and secondary volume even in the replicating state, hence both sides of the replication pair are said to be active. All updates to the secondary volume are also transferred back to the primary volume. When the replication is paused (i.e. placed in the suspended state), the storage system determines the owner volume using the quorum disk and prohibits any read/write access to the non-owner volume.
As with TrueCopy, a bitmap is maintained for pair re-synchronization. When the replication is deleted, the storage system releases the bitmap.
Protector is not be able to operate any dataflow containing a GAD replication if the primary and secondary have been swapped externally, since path resolution will see the original secondaries as the new primaries. The swap must be reversed externally to its normal direction.