Hi Champs,

Today I will explain DR or considering High Availability options in Sitecore Managed Cloud. So without doing any delay, we are going to touch straight to the point and start with a process for recovering your data in the event of an outage, incorporating:

  1. Backup technology
  2. Your secondary environment
  3. The steps of the recovery process
  4. Cost
  5. The recovery point objective (RPO)
  6. The recovery time objective (RTO)

Sitecore Managed Cloud offers three different disaster recovery options that differ slightly in cost and specifications, depending on your requirements. The recovery options available are:

  1. HADR Basic
  2. HADR Hot-warm
  3. HADR Hot-hot

Before we go into an explanation of the above three option, I want to explain basic terminologies in the Sitecore high availability disaster recovery (HADR):

  1. High availability (HA) – A system that aims to ensure an agreed level of operational performance. Usually, the uptime is higher than for the normal period, where the system can failover by itself.
  2. Disaster recovery (DR) – An area of business continuity planning that aims to protect an organization from the effects of significant negative events. Disaster recovery allows an organization to maintain or quickly resume mission-critical functions following a disaster that requires manual intervention.

Now I will explain all three options mentioned above, on a high level one by one as below.

HADR Basic:

With HADR basic, the Sitecore Managed Cloud disaster recovery service sets a process into action in the event of an outage. The steps of this process include:

  1. Scheduling a reoccurring backup, that occurs every 3 hours, of the following assets into the secondary database of the recovery point objective (RPO):
    • The databases.
    • Web applications.
    • The connection strings, (for the credentials).
    • The sizes/tiers of the resources.
  2. Arranging an outage page for customers to see while your site is down.
  3. Setting the traffic manager to switch between the primary Content Delivery (CD) server and the outage page.
  4. Setting up email alerts to notify the Managed Cloud Operations team if the availability tests fail.

HADR Hot-warm:

If you are using the HADR hot-warm option, in the event of an outage the Sitecore Managed Cloud disaster recovery service sets the following process into action:

  1. Deploy a new Sitecore environment in the secondary data center and shut down your web applications.
  2. Use active geo-replication to sync the data between the primary and secondary Azure SQL.
  3. Sync the sizes/tiers of all your Azure resources.
  4. Sync the file contents of all of your web applications.
  5. Set up an outage page to ensure your customers are aware that your site is temporarily down.
  6. Set up a traffic manager to switch between the primary Content Delivery (CD) server and the outage page.
  7. Set up email alerts to notify the Managed Cloud Operations team whenever an availability test fails.

HADR Hot-hot:

In the event of an outage, with the HADR hot-hot option, you must set into motion a recovery a process that is similar to the following:

  1. Enable recovery during a disaster by setting up the necessary environment before the disaster happens.
  2. Initiate the backup and replication process so that the Sitecore deployment and data are available for a healthy recovery.
  3. Deploy a passive Sitecore solution into the secondary region.
  4. Set up and enable the traffic manager to be the public gateway.

Prerequisites:

To set up your disaster recovery process:

  1. Ensure you are running your Sitecore solution (9.1 or later), on Azure.
  2. Install PowerShell with an Azure SDK, version 6.0.0 or later.
  3. Run your setup script and use the relevant modules.
  4. Use PowerShell (AzureRM), to log in to Azure and select the relevant subscription.
  5. Have your Sitecore license file ready.
  6. Have any scripts that you want to develop for your HADR hot-hot scenario ready.
  7. Use the Sitecore Azure Toolkit.

Note:

  1. Sitecore supports the following topologies: XM and XP, and the following deployment sizes: Extra Small, Small, Medium, Large, Extra Large.
  2. You can also use Simple Azure PaaS DR management to create DR of your SMC instances.

Reference:

https://doc.sitecore.com/developers/91/sitecore-experience-manager/en/high-availability-disaster-recovery–hadr-.html

Happy Learning !!!!