Recovery after a Disaster

 

By using Azure Site recovery you can replicate your complete resources residing in one region to another region. Whenever the region 1 goes down due to any disaster you can failover to region 2.

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• We configure DR for our VMs,
• Where they are replicated to some other region
• Make sure RTO and RPO is minimum
• We also perform DR drills to prepare and assess if we are able to make the VMs online within the defined SLA
• Test Failover is performed to test the above

Whenever you plan for a DR, you need to make sure you have sever configuration documented correctly, along with that you would also need all the information for your Servers, networks and applications.

So you need to document all the information in an excel sheet which is called RUNBOOK/Config.

You need Server name, IP Address Private/Public, Server configuration, Network Configuration, High Level Diagram & Low Level Diagram

Application configuration is also documented, for example: Database server, App Server, Web Server etc.

When you do the DR testing at a DR site, there is no time for you to go back and check the IP address or any other information for a server etc. that is when you need the config file/RUNBOOK to be ready.

When we do the DR drill, we make sure to keep the IP address range different for the DR site, form the PROD site…e.g. 192.0.0.0 for PROD and 172.0.0.0 for the DR site….Just to isolate the DR environment while the DR Drill to prevent from any changes on the actual replication or any other live production tasks. We use the Bubble network here to keep changes within and it will not impact the actual environment. 

But the best Practice is to keep the same IP ranges on both the sides, which makes it easy for troubleshooting etc.

For VMware, We use the RVTool, it is a VMware utility that connects to your vCenter server and captures every bit of information about your virtual machines (VMs) and your ESXi hosts that you'd want to know.

But we still need manual efforts for checking the Application mapping etc.

We also have the high level and low level diagrams, in LLD you will find more in depth info, like, what tunneling IP address you are using, what is the PROD IP address, what is the DR IP address, speed of the tunnel, what Firewall are you using, how many VLANS are available, how may network switches are available?

What switch is being used etc…Then, you have the RACK level info. 

We need to make sure that all the above info is timely updated, because the resources keep on changing or rather keep on increasing after every few weeks or months and if this configuration in not updated or maintained in a timely manner. THEN, you are DR Planning in NOT correct.

 Backup is the foundation of any data protection, recovery, retention, and availability strategy — but backup alone isn’t enough. Instead, organizations need to combine backups, snapshots, and replication within a holistic strategy (and within consistent policies), regardless of where data lives across physical, virtual, and cloud infrastructures to achieve both zero downtime and zero data loss.