ASR supports Storage Spaces (S2).
ASR supports Storage Spaces Direct (S2D) for crash consistent recovery points.
ASR supports Scale-out File Server for crash consistent recovery points.

ASR supports LRS, GRS and RA-GRS.
ASR does not support ZRS.

ASR does not support VM disks on Cool and Hot Storage.

The replication data logs with tracked changes first land in a cache storage account in Azure. These logs are processed and the data is stored in an Azure Managed Disk (called as ASR seed disk). The recovery points are created on this disk. Azure Managed Disks are stored as Storage blobs.


UR39 enables support for the latest release of Azure Disk Encryption (Managed Disk, Windows).

UR39 increased data disk size support from 4TB to 8TB.


LRS = Local Redundant Storage
GRS = Geo-Redundant Storage
RA-GRS = Read Access Geo-Redundant Storage
ZRS = Zone Redundant Storage