Implement backup and recovery
📘Microsoft Certified: Azure Administrator Associate (AZ-104)
Azure Site Recovery (ASR) is a service in Azure that helps you replicate, failover, and recover your virtual machines (VMs) and workloads in case of a disaster. Its main purpose is business continuity: keeping applications running even if the primary system fails. In the AZ-104 exam, you need to understand how to set it up, manage replication, and perform failover operations for Azure resources.
1. Key Concepts You Must Know
Before configuring ASR, understand these basic concepts:
a. Recovery Services Vault
- This is a storage container in Azure where recovery points, replication data, and backup data are stored.
- Think of it as a central hub for disaster recovery operations.
b. Replication
- Replication is the process of copying your VM data from one region to another.
- ASR supports replication for:
- Azure VMs to another Azure region
- On-premises VMs to Azure
- Replication ensures if the primary VM fails, the secondary VM in the target region can take over.
c. Failover and Failback
- Failover: Switching operations from the primary site to the secondary site (target region).
- Failback: Returning operations from the secondary site back to the primary site after recovery.
d. Recovery Point Objective (RPO)
- RPO is the maximum acceptable amount of data loss, measured in time.
- Example: If RPO = 15 minutes, you can lose up to 15 minutes of data in a disaster.
e. Recovery Time Objective (RTO)
- RTO is the maximum acceptable time it takes to recover your VM and resume operations.
- Example: If RTO = 1 hour, your VM should be back online within 1 hour after failover.
2. Supported Scenarios for Azure VMs
ASR supports different replication scenarios. For the AZ-104 exam, you need to know:
- Azure-to-Azure replication
- Replicates VMs from one Azure region to another.
- Recommended for regional outages.
- On-premises-to-Azure replication
- Replicates Hyper-V or VMware VMs from your local datacenter to Azure.
- Useful for hybrid setups or moving workloads to Azure.
3. Steps to Configure Azure Site Recovery
Here’s the step-by-step process for configuring ASR for Azure VMs:
Step 1: Create a Recovery Services Vault
- Go to the Azure portal → All services → Recovery Services vaults → Create.
- Choose:
- Name of the vault
- Subscription
- Resource group
- Target region (where recovery data will be stored)
Step 2: Prepare the Source VM
- Ensure the VM you want to protect is supported for replication.
- Install the ASR agent if required (mainly for on-premises VMs).
Step 3: Configure Replication
- Inside the vault, select “+ Replicate”.
- Choose the source and target:
- Source: Azure VM, Hyper-V VM, or VMware VM
- Target: Target Azure region
- Choose replication policy:
- Frequency of data replication
- Retention period for recovery points
- RPO and RTO targets
Step 4: Enable Replication
- After configuring, enable replication.
- ASR starts copying the VM data to the target region.
- You can monitor progress in Recovery Services Vault → Replicated Items.
Step 5: Test Failover
- Test failover allows you to verify that the replicated VM works in the target region without affecting the production VM.
- Steps:
- Select the VM → Test Failover
- Choose a recovery point to test
- Create a temporary network to run the VM safely
- This ensures your disaster recovery plan works.
Step 6: Perform Planned or Unplanned Failover
- Planned failover: Used when you know the primary VM will go offline (e.g., maintenance). No data loss.
- Unplanned failover: Used when a disaster occurs unexpectedly. May result in minimal data loss depending on RPO.
Step 7: Failback
- Once the primary site is restored, failback the VM:
- Reverse replication from the secondary site to the primary site.
- Resume normal operations.
4. Monitoring and Managing ASR
In the Azure portal:
- Recovery Services Vault → Replicated Items:
- Shows VMs being replicated
- Status: Healthy, Warning, or Critical
- Alerts and notifications can be configured to monitor replication health
- Audit and logs can be viewed using Azure Monitor for compliance and troubleshooting
5. Important Exam Notes
For AZ-104, make sure you know:
- ASR is not just backup—it is for disaster recovery and business continuity.
- Key exam terms: Recovery Services Vault, replication, failover, failback, RPO, RTO.
- You can replicate Azure VMs to another region using ASR.
- Test failover is non-disruptive, while actual failover may disrupt production.
- Planned vs unplanned failover—planned ensures no data loss.
- Recovery points and replication policies must be configured correctly.
- You may also need to know network and storage dependencies for replicated VMs.
6. Summary Table for Quick Exam Reference
| Concept | Description |
|---|---|
| Recovery Services Vault | Stores replication data and recovery points |
| Replication | Copying VM data to a secondary site or Azure region |
| Failover | Switching operations to secondary VM during disaster |
| Failback | Returning operations back to primary VM |
| RPO | Max data loss allowed |
| RTO | Max downtime allowed |
| Test Failover | Verify replication without affecting production |
| Planned Failover | Scheduled downtime, no data loss |
| Unplanned Failover | Unexpected downtime, minimal data loss possible |
✅ Tip for Students: Focus on understanding the workflow: Create vault → Configure replication → Test failover → Perform failover → Failback. The AZ-104 exam often tests scenario-based questions, so knowing these steps is crucial.
