locally redundant storage (LRS)
copies on 3 different racks within the same availability zone
zone-redundant storage (ZRS)
copies in 3 different availability zones
multiple region
geo-redundant storage (GRS)
copies on 3 different racks in the primary region (LRS) &
copies on 3 different racks in the paired region (LRS)
geo-zone-redundant storage (GZRS)
copies in 3 different availability zones in the primary region (ZRS) &
copies on 3 different racks in the paired region (LRS) <== asymmetric