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Azure Backup

Disaster Recovery Solutions for Azure: What You Need to Know

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As organizations continue to move full steam ahead into the cloud, disaster recovery for applications hosted in the cloud is more important than ever. With Azure, users have multiple business continuity and Azure backup tools to meet their application Recovery Point Objectives (RPOs) and Recovery Time Objectives (RTOs).

In this blog we will explore the need for cloud based disaster recovery as a service (DRaaS), the options currently available for Azure customers, and how these disaster recovery solutions have an edge over other solutions in the market. We will also discuss how NetApp Cloud Volumes ONTAP complements the disaster recovery solutions on Azure so your enterprise can cover all your business continuity requirements.

How Do You Deal with a Site Failure?

Disaster Recovery as a Service (DRaaS) refers to an orchestrated service that can ensure that your applications are moved seamlessly to a secondary, DR location in the cloud should the primary hosting region become unavailable.

A DRaaS service provider should be able to provide a solution with fine-grained controls such as configurable replication intervals, control of the failover and failback mechanisms, non-disruptive testing, automation for pre- and post-failover activities, and more. Azure Site Recovery (ASR) is one such solution for handling planned or unplanned site failures.

ASR is an Azure-native service that can be used in cloud-only and hybrid architectures, catering to multiple workloads in varying platforms. It is worth mentioning that ASR was given an “Excellent” rating by due to this versatility to protect against cloud outages.

Disaster Recovery Solutions in the Cloud

The different DR strategies available for customers in leading cloud platforms can be summarized as follows:

  • Make periodic backups of your application data to a storage account in a DR site and spin up a new environment manually by restoring the data to that DR site in the event of a disaster.
  • Continuous replication of VMs with all disks to a cloud storage environment so that you can fire up the VMs directly on the target cloud environment while triggering the DR plan. For the failover to be effective, replication should be consistent and application-aware.
  • Synchronizing applications and dependencies to the target cloud platform so that they can be restored in an orchestrated manner. This is the recommended approach for business-critical applications as it helps to ensure business continuity with minimal manual intervention.

AWS and GCP DR Solutions

Neither AWS nor GCP has an end-to-end native solution for DR. They do have some alternative solutions for configuring DR, but these can be complex. 

AWS recommends four architectures for customers to implement their own DR solution. Customers can go for a basic backup/restore option which could be configuration-intensive and time consuming. A pilot light, or “warm,” standby approach can be used where a scaled-down environment is kept ready to take over during a DR scenario. Multi-site deployment involves a full-fledged environment deployed to two sites with load balancing configured to take care of outages. Though pilot light, warm standby, and multi-site deployments provide better turnaround times when compared to backup/restore, it could increase the overall cost of the solution, as additional resources should be deployed and kept running in the cloud to keep the lights on. Read more about AWS backup solutions here.

GCP provides similar suggestions for building a DR solution. GCP customers can use either warm, cold, or hot approaches to data replication and application standby models to achieve business continuity. Like AWS, these are also do-it-yourselves approaches rather than a well-thought-out tool that can serve as an end-to-end DR solution.

Azure Outage Solutions

Important mission-critical workloads, such as Azure databases, require a high level of protection. There are several Azure options for this, including Azure Backup and Azure Site Recovery.

Azure Backup for Azure VM Backups

Azure Backup offers a completely cloud-based solution to protect your Azure VMs from platform outages, data corruption, or manual errors. It can also be used to protect your workloads that are hosted on-prem through deployment of a lightweight agent/server depending on the use case.

Azure Backup data is stored in highly available Azure storage with unlimited free data transfers for backup and restore. The backup data is application consistent so that it is always usable after a restoration. Data at rest and in transit are always encrypted. The passphrase used for encryption is solely owned and operated by the customer.

There is no time-bound restriction for data retention and customers can store up to 9999 recovery points of an instance at any given time.

Azure Site Recovery for Azure Failover and Failback

Azure Site Recovery (ASR) offers a comprehensive DR solution for failover and failback of on-premises workloads and Azure Virtual Machines. It can protect on-premises workloads in physical servers, Hyper-V, VMWare by data replication and failover to Azure in the event of a disaster. Azure acts as a low-cost DR alternative, where the data is replicated and readily available with near real-time replication intervals.

With ASR, Azure VMs can be replicated to a different region to protect against platform outages and regional disasters with a built-in failback mechanism. The service is application aware, supporting replication and recovery of enterprise workloads and services including SAP, Web apps, Active Directory (AD), DNS, SharePoint, Dynamics AX, and more.

ASR Benefits

  • Charged by a flat rate per protected instance plus the storage cost for storing the backup data on a pay-as-you-go basis.
  • Single pane management of all DR configurations, whether hosted on-prem or in Azure.
  • Resilient underlying storage with multiple copies of the data in geographically-paired regions.
  • Data is encrypted at rest and in transit using customer managed keys. The service can cater to on-premises, cloud, as well as hybrid architectures.
  • Customizable recovery plans to define the order of component failover and failback.

Azure Site Recovery Architecture for Data Replication

Azure Site Recovery uses different components depending on the architecture in use. Replication can be directly enabled for VMs from the Azure portal, which is also where the Azure Site Recovery extension is installed. For replicating on-premises VMs, certain additional components will be required depending on the architecture.

Replicating VMware data to Azure using ASR involves the following components:

  • Process Server: Caches, compresses, and encrypts data sent to Azure from the source.
  • Config Server: Centralizes management of the replication from the source.
  • Mobility Service: Captures data writes from memory in the VMs.
  • Master Target server: Replicates data back to the primary site during failback.

Replication of Hyper-V-based environments to ASR involves the following components:

  • ASR provider: Orchestrates and manages replication from the Virtual Machine Manager (VMM).
  • Recovery services agent: Handle data replication from each Hyper-V.
  • HRL files: Tracks changes to each hard disk in separate Hyper-V Replication logs(.hrl) files for the initial sync as well as for delta replication.

Get More with Cloud Volumes ONTAP

While Azure offers some capable disaster recovery solutions on its own, users can get more protection and better DR processes, all at a lower cost, with NetApp Cloud Volumes ONTAP

Cloud Volumes ONTAP brings the trusted enterprise-class storage management features of on-prem ONTAP storage systems to Azure. It can reinforce your DR strategy in Azure, serving as the underlying storage management system, or serve as a DR storage management on its own. In either case, Cloud Volumes ONTAP adds value with features such as data replication, high availability, and storage efficiency, as we’ll see below.

Ensure Cloud Business Continuity
The Cloud Volumes ONTAP HA (High Availability) configuration for Azure uses shared storage between two Cloud Volumes ONTAP nodes that are part of different fault and update domains. In the event that one of the nodes becomes unavailable,  the surviving node takes over and provides access to data without any disruption.

Easy Azure storage replication
Cloud Volumes ONTAP uses SnapMirror® technology to replicate data across hybrid and multicloud architectures. It can be used to replicate data to a secondary site for DR and keep it in sync. SnapMirror replication is set up using the simple drag-and-drop controls in OnCommand® Cloud Manager.

Failover and Failback
A failover can be initiated by breaking the replication relationship in SnapMirror. During failback the synchronization can be reversed and data from the DR site can be replicated back to the primary location.

Storage Efficiencies
Cloud Volumes ONTAP’s storage efficiency features, including thin-provisioning, data compression, deduplication, and data tiering, help to reduce the DR copy’s storage footprint and costs. These features are available out of the box and can be used by the customer with no configuration overheads.

FlexClone for DR Testing
Cloud Volumes ONTAP data cloning  technology can be used to clone instant, writable volumes for DR testing that won’t affect ongoing operations. These volumes are created instantly, and with zero capacity penalty.


Cloud-based disaster recovery solutions are complex architectures that involve lots of moving parts and configuration. The alternative option is to take advantage of DRaaS solutions such as Azure Site Recovery combined with Cloud Volumes ONTAP for DR.

Used with or without ASR, Cloud Volumes ONTAP makes the DR process easy for you through options for fast replication and synchronization, data cloning, and automatic failover of data to Azure.

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Yifat Perry, Technical Content Manager

Technical Content Manager