Azure Blob Storage Failover

Introduction

The following procedures are applicable to customers using Azure GRS or Azure GZRS. These storage classes offer asynchronous geo replication. Customers do not need to account for separate credentials or an endpoint for the secondary copy. Azure manages that through the GRS and GZRS storage class service. This means that there is no need for Nasuni Support to change configuration settings.

Failover is triggered through the Azure portal.

Note: Nasuni recommends using this process only in a complete disaster recovery scenario, and it requires Nasuni's direct involvement.

Azure Controlled Failover

A controlled failover ensures that unprotected data in the cache is protected.

The customer performs all parts of this procedure.

To perform an Azure controlled failover, follow these steps:

1. On all the Nasuni Edge Appliances connected to the volume:

   1. Convert all shares of the volume to Read Only.
      On the Edge Appliance UI, on the Volumes page, select the volume, click Total Shares, and select Read Only Share.
      On the Nasuni Management Console (NMC), on the Shares page, select a share, click Edit, and select Read Only Share.

   2. Perform a final snapshot on the volume.
      On the Edge Appliance UI, on the Volumes page, for the volume that you want to take a snapshot of, click Take snapshot now.
      On the Nasuni Management Console (NMC), on the Volumes page, for the volume that you want to take a snapshot of, click Take snapshot now.

2. Using the Azure portal, navigate to the storage account, select Redundancy, and click "Prepare for failover".

3. After the GRS or GZRS service replication fully completes successfully, obtain the last successfully completed sync time, and ensure that it is later than the last Nasuni snapshot from step 1.b.
   

4. Click Failover and type 'yes' to confirm.

5. When failover completes on all Nasuni Edge Appliances connected to the volume, perform these steps:

   1. Convert all shares to the appropriate Read/Write access permission.

   2. Test the snapshot process.

Azure Uncontrolled Failover

An uncontrolled failover DOES NOT ensure that unprotected data in the cache is protected. Data loss is possible.

The customer performs some parts of this procedure, and Nasuni Support performs other parts of this procedure.

To perform an Azure uncontrolled failover, follow these steps:

1. On all the Nasuni Edge Appliances connected to the volume, disconnect from the shared volume.

2. On the Nasuni Edge Appliance that owns the volume, disable remote access to the volume.

3. Obtain the last successfully completed GRS or GZRS sync time from your Azure account and provide that to Nasuni Support.
   

4. Using the Azure portal, navigate to the storage account, select Geo-Replication, and click “Prepare for failover”.

5. Nasuni Support provides the Nasuni NOC team with the timestamp provided by the customer.

6. When the failover process in step 4 completes, the customer performs a recovery process on the Nasuni Edge Appliance that owns the volume, with the assistance of Nasuni Support, if necessary.

   1. Re-share the Volume and connect to other Nasuni Edge Appliances with appropriate share read/write access.

   2. Test the snapshot process.

7. Nasuni Support, on all Nasuni Edge Appliances, tests the snapshot process.