vSAN Stretched Clusters: High Availability for Disaster Avoidance Environments

In today’s digital age, data centers are the backbone of any organization’s operations. The availability and accessibility of data are critical to ensure business continuity. However, natural disasters, human errors, and other unforeseen events can lead to data loss and downtime, causing significant financial and reputational damage. To mitigate these risks, organizations need a robust disaster avoidance strategy that ensures high availability and business continuity. One such solution is vSAN Stretched Clusters, introduced in vSAN 6.1.

vSAN Stretched Clusters provide an active-active architecture that spans two different physical locations, offering high availability and disaster avoidance capabilities. In this blog post, we will explore the use cases, requirements, and best practices for implementing vSAN Stretched Clusters in your data center environment.

Use Cases for vSAN Stretched Clusters:

vSAN Stretched Clusters are ideal for organizations that require high availability and disaster avoidance capabilities. These use cases include:

1. Disaster recovery: By using two different physical locations, vSAN Stretched Clusters can help you recover from a disaster by simply failing over to the secondary site.

2. Business continuity: With vSAN Stretched Clusters, you can ensure business continuity by providing access to your applications and data even in the event of a disaster.

3. Geographically dispersed data centers: If you have multiple data centers located in different geographic locations, vSAN Stretched Clusters can help you consolidate your storage resources and provide high availability across all sites.

Requirements for vSAN Stretched Clusters:

To implement vSAN Stretched Clusters, there are several requirements that must be met:

1. ESXi hosts: ESXi hosts must be placed in two different physical locations and connected with high bandwidth, low latency networking.

2. Networking: Networking requirements include 1GbE or higher links between sites, and MTU settings should be set to 9000 for optimal performance.

3. Witness node: A witness node is required to maintain the consistency of the cluster. The witness node can be a dedicated physical ESXi host or a specialized virtual witness appliance.

4. Fault domains: Hosts must be grouped based on their physical locations and placed in two different fault domains to ensure high availability.

Best Practices for vSAN Stretched Clusters:

Here are some best practices to follow when implementing vSAN Stretched Clusters:

1. Evenly spread hosts: Ensure that hosts are evenly spread between the two sites to maintain a balance of resources and avoid overloading any single site.

2. Monitoring: Regular monitoring of the cluster is crucial to ensure high availability and business continuity. Use tools like vSphere monitoring and reporting to monitor the health of your cluster.

3. Maintenance: Plan regular maintenance windows to ensure that both sites are up-to-date with the latest software updates and patches.

4. Failover testing: Test failover scenarios regularly to ensure that the cluster can fail over seamlessly between sites in case of a disaster.

Conclusion:

vSAN Stretched Clusters provide a robust solution for disaster avoidance and high availability in data center environments. By implementing vSAN Stretched Clusters, organizations can ensure business continuity, protect their applications and data, and minimize downtime due to disasters or human errors. Remember to follow best practices such as evenly spreading hosts between sites, monitoring the cluster regularly, and testing failover scenarios to ensure high availability and business continuity.