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Proven Practices to Troubleshoot Failures in vSphere vSAN Storage Clusters

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In a VMware vSphere environment, vSAN storage clusters are critical in providing high Availability and efficient storage solutions. However, vSAN clusters can encounter common failures that impact performance and data availability like any technology.

This blog will explore these common vSAN failures, provide troubleshooting tips, and share best practices to ensure your vSphere environment runs smoothly.



Before we dive into troubleshooting common vSAN failures, ensure you have the following prerequisites in place:

  1. Access to a vSphere environment with vSAN storage clusters.
  2. A basic understanding of vSphere concepts and components.
  3. Administrative access to your vSphere infrastructure.

Understanding vSAN Storage Clusters


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What is vSAN?

vSAN, or VMware vSphere Storage, is a software-defined storage solution aggregating local or direct-attached storage devices from ESXi hosts into a shared storage pool. It is the backbone of vSphere environments and provides essential features like hyper-converged infrastructure, high Availability, and scalability.


Benefits of vSAN

High Availability: vSAN enhances the Availability of your virtualized workloads by providing redundancy and fault tolerance. It is a driven HCI-based storage solution.

Scalability: It allows for easy storage capacity and performance scaling as your data center grows.

Performance: vSAN optimizes storage performance with features like caching and deduplication.


Common Failures in vSAN Storage Clusters

Network Failures

Network failures can disrupt communication between ESXi hosts in the cluster, causing data unavailability. For example, if the NIC of any one ESXi host contributes to the vSAN Cluster, communication is lost.

Troubleshooting Tip:  Regularly monitor network health, configure proper network redundancy, and promptly isolate and address network issues.

Disk Failures

Disk failures can lead to data loss or unavailability in the cluster. From your disk group, Cache disk failure can lead to the inaccessibility of the entire Disk Group. The capacity disk’s failure may reduce the entire cluster’s overall capacity. Both situations are undesirable.

Troubleshooting Tip: Implement disk redundancy with vSAN’s RAID-1 mirroring, use high-quality storage devices, and maintain proactive disk health monitoring.

Host Failures

If an ESXi host fails, it can impact the cluster’s performance and data availability. Even if we put the host into maintenance mode for a short time or longer, VMs will become inaccessible.

Troubleshooting Tip: Configure vSAN’s fault domains to isolate host failures and set up VM restart priorities in case of host failures using vSphere HA and DRS.

Troubleshooting and Best Practices

Use Monitoring Tools:  Utilize vSAN health checks, vCenter alarms, and log analysis tools to identify and resolve issues. Please refer to VMware vSAN Skyline Health documentation for a detailed explanation.

Maintain Performance Optimization: Regularly monitor and tune storage performance using vSAN’s performance service and optimize storage policies for different workloads.

Take care of Redundancy and Data Protection:  Configure redundancy with RAID-1 mirroring, set up data at rest encryption, and maintain data protection by creating backups or snapshots.



vSAN storage clusters are the backbone of a vSphere environment, providing robust storage solutions for virtualized workloads. However, understanding common failures, troubleshooting tips, and best practices is essential for maintaining the health and availability of your data. By proactively addressing issues and following best practices, you can ensure that your vSAN clusters operate at their best, providing reliable storage and high availability for your virtual infrastructure. Stay vigilant, monitor regularly, and apply best practices to keep your vSAN storage clusters in shape.

With this blog, you’ll be better equipped to address and prevent common failures in your vSAN storage clusters, ensuring the continued success of your vSphere environment.


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About CloudThat

Incepted in 2012, it is the first Indian organization to offer Cloud training and consultancy for mid-market and enterprise clients. Our business aims to provide global services on Cloud Engineering, Training, and Expert Line. The expertise in all major cloud platforms, including Microsoft Azure, Amazon Web Services (AWS), VMware, and Google Cloud Platform (GCP), position us as pioneers in the realm. 

WRITTEN BY Rahulkumar Shrimali



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