A use case for consistency groups is when you want to resume operations by using consistent data for circumstances in which the most recent data is inaccessible.
If GAD pairs change to the Suspended state, I/O from servers continues only for the volume that has the most recent data. While GAD pairs are in the Suspended state, if a failure occurs in the storage system that has the most recent data, thus making it impossible to access the most recent data, you can resume operations from the point when GAD pair suspension started by using the consistent data (old data).
For example, assume that GAD pairs changed to the Suspended state due to a path failure of the primary volume. At this point, the primary volume has finished performing the write operation data up to data B.
Then, a failure occurred in the storage system of the secondary volume, making it impossible to access the most recent data in that volume. In such a case, after deleting the GAD pairs, you can resume the write processing for data C by using the primary volume.