What is vSAN?

What is vSAN?

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VMware vSAN is a software-defined storage ultimate solution from VMware to eliminate the need for additional storage boxes using your local storage server. In plain language, vSAN abstracts the local storage of ESXi hosts and makes it a highly optimized pool of shared storage.

Consequently, since you use local storage, you will not need an additional storage box for file storage, which also helps reduce the total cost of ownership (TCO). vSAN is a virtual clustered data store that uses local storage of ESXi hosts and builds a logical storage pool represented in the form of a data warehouse for ESXi hosts.

One of the most valuable characteristics of the vSAN datastore is that it supports all kinds of VMware vSphere features like vMotion, Storage vMotion, DRS, HA, etc., to ensure the virtual machine with the appropriate configuration.

Because it is already integrated into the hypervisor, there is no need to install additional appliances. With a stretch cluster, node, and ROBO – remote office/back office – deployment options, using All-Flash or Hybrid modes, vSAN proves to be incredibly flexible.

Also, with the release of VMware vSAN 7 Update 3, administrators can even secure the storage of traditional, non-virtualized hosts through highly available NFS stocks and iSCSI devices. A vSAN clusters are also available to manage to compute and storage quality.

Traditional SAN

Now, let’s look at the beginning of virtual SAN (vSAN). Traditional Storage Area Network (SAN) consists of physical devices connected to handle block-level data volume.

This type of disk-based storage provides outstanding performance for critical structured workloads. Traditional SAN appliances are expensive and difficult to maintain.

SAN is looking for a team of experts who can fix hardware problems, monitor resource consumption and usage, and ensure everything runs smoothly.

vSAN Datastore and Networking

VMware vSAN combines persistent disks in your hosts over a vSAN network to create a single shared data store. Each ESXi host has pre-installed server software, allowing virtual machines to access their drives without particular configuration.

It also means that VMs should not run on the same hosts where their files are physically stored. Shared storage allows functions such as vMotion, DRS, and HA to work without a traditional SAN. Like any other shared storage protocol, vSAN needs network access.

The vSAN network can go through L2 or L3 as required. Therefore, keep in mind that vSAN traffic is not balanced with loads over multiple NICs, as NIC pooling is used for redundancy and failure.

VMware vSAN system requirements

Although vSAN is easy to set up, there are some things you need to know before deploying a virtual SAN in your environment:

  • 10 GB NIC – 1 GB NIC is recommended;
  • RAID or SAS/SATA HBA controller;
  • At least one permanent storage disk, HDD or flash drive, and one flash cache device for each node contribute to capacity.

How vSAN works

Virtual SAN requires no additional software to install and can be enabled with a few simple clicks. It is managed by the vSphere Web Client and integrates with the VMware set.

Understanding the components of the vSAN architecture, even because it is easy, does not give you a free license to learn how it works. You will probably have to discover things and want to know the basics.

But other than the practical advantage, learning how it works is pretty cool. Understanding how everything works make it a thousand times easier to figure out how to fix it when things go wrong.

Understand the components of vSAN Architecture

Roles on the vSAN server

Since no host can communicate with any other host, each host will be in its partition, and its node “master” will be named.

There is a master who is responsible for receiving updates from all nodes from CMMDS, the service for clustering and distributing those updates to agents.

Main vSAN components

  • Cluster-Level Object Manager (CLOM);
  • Cluster Membership, Monitoring, and Directory Services (CMMDS);
  • Reliable Datagram Transport (RDT);
  • Distributed Object Manager (DOM);
  • Local Log-Structured Object Manager (LSOM).

Key features of VMware vSAN

Once you understand what VMware vSAN is, you need to be familiar with the key features of a virtual storage network.

  • Software-defined

It is an entirely software-defined storage solution as the virtual storage area network progresses on the virtual SAN appliance.

  • Compression and deduplication

vSAN is very suitable for space-saving features such as compression and deduplication.

  • Simple configuration

Impeccably simple to configure and operate.

  • VMware vSphere integration

Minimizes memory and CPU depletion and improves performance.

  • Flexibility

It is not an effort to increase and decrease vSAN as required.

  • Storage policy

Different storage policies can be configured by disk or VM—to assist in balancing and automating VM storage provisioning. Storage policy-based management is of utmost importance to VMware ESXi.

  • Hybrid or flash

vSAN fully supports flash and hybrid architectures using Flash drives in which magnetic disks and cache will be used in the form of capacity. Hybrid cloud management for virtual machines is an awesome feature to have.

  • Encryption

vSAN supports data encryption that is intended for storage in the vSAN datastore. It uses AES 256 for encryption purposes.

VMware vSAN storage optimization features


Duplication reduces the printout of data by removing excess copies of the same file across multiple storage devices.

By ensuring that deduplication is a feature of your vSAN, you can reduce storage costs and get the most out of your investment.

Synchronous/Asynchronous replication

Synchronous replication is a technology that ensures data integrity and prevents data loss during system failures or disasters, such as earthquakes or fires. Likewise, it synchronizes all records in primary storage before clients confirm them.

Asynchronous replication only copies modified blocks to optimize network bandwidth usage without sacrificing the protection of your organization’s most valuable data.

Thin provisioning

Thin provisioning is a storage optimization feature that sustains organizations to save space by just using the disk capacity they need at all times.

With VMware vSAN, which offers light security, you can reduce the total cost of ownership (TCO) and expand your resources while still meeting your business needs for confidential data access.

SSD caching

SSD caching is another top feature that should be included in your vSAN.

By caching an SSD, you can use a fast but expensive storage technology called Hard Disk Drive (SSD) as a temporary buffer for slower drives such as rotating drives or hard drives.


Virtualization is a cornerstone of today’s corporate IT infrastructure. VMware vSAN is a popular choice among companies that want to simplify storage management while achieving agility and TCO reduction. Despite KVM, Hyper-V, and Citrix Hypervisor competition, VMware vSphere still dominates the virtualization market.

The virtual SAN device allows the unused storage capacity of the virtual servers to be connected and access the virtual servers as needed. A virtual SAN device is usually downloaded as a software program running on a virtual machine.

VMware-ESXi.com will continue in its pursuit of giving our regular readers a bit of effective content related to VMware advances, whether about any virtual storage appliance, storage resources, or a vSAN cluster.

Yet, some storage hardware vendors are beginning to incorporate virtual SANs into their firmware. Depending on the vendor, a vSAN device may also be called a software-defined storage device (SDS) or simply a virtual storage device.