If you're running VMware vSAN, it's critical to configure it properly with Fault Domains and a Stretched Cluster to ensure high availability. Without this setup, a single host failure could take down your entire storage infrastructure—precisely what happened to a new client we recently onboarded.
What Went Wrong?
During an IT assessment, we reviewed a four-host vSAN cluster for a new client and were shocked to find that their storage was not configured correctly. If any host went down, all vSAN storage became unavailable—a disaster waiting to happen. The previous IT provider had not implemented a Fault Domain or a Stretched Cluster, undermining the use of vSAN for high availability.
Why Fault Domains and Stretched Clusters Matter
- Fault Domains ensure data redundancy across different hosts, preventing a single point of failure.
- A Stretched Cluster allows vSAN storage to remain accessible even if a host fails.
In VMware's terminology, a Stretched Cluster can often refer to geographically separate sites, but in this context, it means ensuring local storage redundancy across hosts.
How We Fixed It
We reconfigured the client’s vSAN setup by:
✔️ Implementing Fault Domains to distribute data properly.
✔️ Configuring a Stretched Cluster - so losing one host doesn’t bring down the entire storage.
✔️ Testing the setup to confirm high availability and seamless failover.
Now, their infrastructure is resilient, and they no longer have to worry about storage outages due to a single host failure.
Don’t Make the Same Mistake
If you’re running vSAN, double-check your setup. If you’re unsure whether your system is configured correctly, we can help. ADS Consulting Group has extensive experience optimizing vSAN for high availability.
Need assistance? Email us at info@adscon.com.
Want more IT insights? Subscribe to our YouTube channel for weekly tech tips.