SoftNAS Data Recovery with Azure Storage Replication
The level of DR preparedness a customer chooses to deploy is at the customer's discretion. A customer has the option to deploy standby SoftNAS VMs, stopped and ready to be started in the event of an Azure geo-failover. But the process of fully configuring the SoftNAS VMs in Region B after an Azure geo-failover is a manual process that can only take place after Azure completes the geo-failover process. (note: the Azure geo-failover process is a manual process as well, and may take days to complete).
See the diagram on the right for a depiction of this standby deployment:
*The Standby SoftNAS HA Nodes are simply SoftNAS nodes that have been launched in Region B and stopped in preparation for an Azure geo-failover
**The Standby SoftNAS Nodes are not connected to any Azure Storage Account while in standby, being the Storage Account with the replicated data in Region B is not accessible until after Azure performs a geo-failover (RA-GRS may provide read-only access, but as of this time we are not sure if the storage account used for the read-only RA-GRS access will represent the same storage account that would be used during a post geo-failover event).
Expected steps to recover from a geo-failover with SoftNAS
(These steps have not been formally verified by SoftNAS)
After Azure has performed a geo-failover, the below is expected stated of the Azure Region B based on Azure documentation:
- No access to Azure Region A available.
- The data that has been replicated to Region B is now R/W accessible through the same Azure storage account that was used to connect to it in Region A.
- The data is no longer being replicated by Azure
Assumed SoftNAS steps after an Azure geo-failure:
- SoftNAS VMs would need to be launched in Region B, or the standby SoftNAS VMs started if they exist.
- The Azure storage that was replicated would need to be imported into the Region B SoftNAS VMs using the same Azure storage account.
- Any application that was previously accessing SoftNAS in Region B would need to have its DNS changed to now point to the SoftNAS servers in Region B.
- If the SoftNAS HA pair in Region A was in a failure state when Region A was lost, recovery options on Region B after the above steps could have complications, being Azure clearly indicates that data may have been lost during a geo-failover.