vSAN Deployment Options

We can build a vSAN Cluster by selecting individual software and hardware components, such as drivers, firmware, and storage I/O controllers that are listed in the VMware Compatibility Guide website. When designing a vSAN cluster, use only devices, firmware, and drivers that are listed on the VMware Compatibility Guide website. Using software and hardware versions that are not listed in the VCG might cause cluster failure or unexpected data loss.

In this short post, lets have a quick look at the different vSAN Deployment options. vSAN can be deployed in different ways.

1. Standard vSAN Cluster

A standard vSAN cluster consists of a minimum of three hosts. Typically, all hosts in a standard vSAN cluster reside at a single site, and are connected on the same Layer 2 network. All-flash configurations require 10 Gb network connections, and vSAN Express Storage Architecture requires 25 Gb network connections.

2. Two-Node vSAN Cluster

Two-node vSAN clusters are often used for remote office/branch office environments, typically running a small number of workloads that require high availability. A two-node vSAN cluster consists of two hosts at the same location, connected to the same network switch or directly connected. You can configure a two-node vSAN cluster that uses a third host as a witness, which can be located remotely from the branch office. Usually the witness resides at the main site, along with the vCenter Server.

A single witness host can support up to 64 two-node clusters. The number of clusters supported by a shared witness host is based on the host memory.

3. vSAN Stretched Cluster

The vSAN Stretched Cluster feature was introduced in vSAN 6.1. A vSAN stretched cluster provides resiliency against the loss of an entire site. The hosts in a stretched cluster are distributed evenly across two sites. The two sites must have a network latency of no more than five milliseconds (5 ms). A vSAN witness host resides at a third site to provide the witness function. The witness also acts as tie-breaker in scenarios where a network partition occurs between the two data sites. Only metadata such as witness components is stored on the witness.

With this I'll wrap up this post here.

In the next few blogs we will discuss on how to create a standard vSAN Cluster.

Thank you for reading!

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