There are many people who do not understand the performance of vsan6.7, so today Xiaobian is here to share a little of my experience, I hope it can help you.
VSAN 6.1 allows you to build a StretchedCluster between two sites in different geographical locations by synchronizing data.
This effectively provides low-cost, highly reliable hypermetro storage for vSphere virtual machines, providing continuous availability.
Similar to the hypermetro scheme of external disk arrays, it has strict requirements on the network. Data synchronization between two sites requires high bandwidth and low latency. VSAN also requires a delay of less than 5ms.
In addition, the Witness node is required for an extended VSAN cluster. The witness node stores only metadata but not service data
It sets up a heartbeat between the two sites. When one of the sites goes down or a network partition occurs between the sites, Witness can determine what is happening and decide how to ensure availability.
The delay between the Witness node and the other two sites can be less than 100ms. The Witness node does not have to run on a physical ESXi host, but can also run on a virtual machine at a third site, or can run on the public cloud vCloud Air.
VMware has already prepared a special Witness virtual Appliance, which is essentially a virtual machine with ESXi installed.