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:
- Backup technology
- Your secondary environment
- The steps of the recovery process
- The recovery point objective (RPO)
- 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:
- HADR Basic
- HADR Hot-warm
- 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):
- 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.
- 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.
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:
- 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.
- Arranging an outage page for customers to see while your site is down.
- Setting the traffic manager to switch between the primary Content Delivery (CD) server and the outage page.
- Setting up email alerts to notify the Managed Cloud Operations team if the availability tests fail.
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:
- Deploy a new Sitecore environment in the secondary data center and shut down your web applications.
- Use active geo-replication to sync the data between the primary and secondary Azure SQL.
- Sync the sizes/tiers of all your Azure resources.
- Sync the file contents of all of your web applications.
- Set up an outage page to ensure your customers are aware that your site is temporarily down.
- Set up a traffic manager to switch between the primary Content Delivery (CD) server and the outage page.
- Set up email alerts to notify the Managed Cloud Operations team whenever an availability test fails.
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:
- Enable recovery during a disaster by setting up the necessary environment before the disaster happens.
- Initiate the backup and replication process so that the Sitecore deployment and data are available for a healthy recovery.
- Deploy a passive Sitecore solution into the secondary region.
- Set up and enable the traffic manager to be the public gateway.
To set up your disaster recovery process:
- Ensure you are running your Sitecore solution (9.1 or later), on Azure.
- Install PowerShell with an Azure SDK, version 6.0.0 or later.
- Run your setup script and use the relevant modules.
- Use PowerShell (AzureRM), to log in to Azure and select the relevant subscription.
- Have your Sitecore license file ready.
- Have any scripts that you want to develop for your HADR hot-hot scenario ready.
- Use the Sitecore Azure Toolkit.
- Sitecore supports the following topologies: XM and XP, and the following deployment sizes: Extra Small, Small, Medium, Large, Extra Large.
- You can also use Simple Azure PaaS DR management to create DR of your SMC instances.
Happy Learning !!!!