In this blog we will have a look at vSAN 8 new and improved features. Or as the title already gave away: vSAN 8 New and improved explained.

vSAN has been around for 8 years or so and during that time has evolved from a simpel Software defined storage solution on which I would not run production workloads to a fully capable and mature product.

New features are added all the time like: All flash, Deduplication, Encryption and even file services. Other major concerns in the past where how vSan dealt with failures and maintenance but also here VMware has made some major improves over time.

So with this intro out of the wat let’s dive into what is new with vSAN 8 shall we?

vSAN Express Storage Architecture or ESA

With the introduction of vSan 8 VMware has brought in the vSAN Express Storage Architecture (ESA).
vSAN ESA is a new optional storage architecture next to the already existing architecture (Original Storage Architecture or OSA).

This new architecture is designed with the following new features and improvements:

  • Making use of high performance NVMe-based flash drives
  • Scalable high-performance native snapshots
  • Deduplication and compression handeling improvements
  • Elimination of using disk-groups, all disks contribute to caching and capacity storage (No need for separate cache devices anymore, more on that in a bit)
  • Enhanced availability and resiliency by reducing failure domains and improving availability using storage pools
Source: VMware

vSAN ESA: No more Cache disks and Disk groups

In the Original Storage Architecture there was the need for Cache disks and Disk groups. Gone are the days of expansive Optane drives as cache disks. But also no more disk groups, we now have Storage pools.

Source: VMware

New Log-Structured File System

With vSAN ESA also comes a new Log-structered file system. This file system is created to ingest writes quickly and efficiently specifically for flash devices.

It reduces the compute and network resources needed to implement the vSAN 8 solution.

Log-Structured File system features:

  • Reduced I/O amplification
  • Low overhead
  • Compatibility with future device types

Source: VMware

Log Structured Object Manager in vSAN ESA (LSOM)

High performance with NVMe drives require several improvements over “normal” drives. These improvements are made in the lowest level of the stack in the Log Structured object manager.

The LSOM is a high performance block engine and a key value store. Enabling the delivery of large write payloads and minimising the overhead of meta writes. These are necessary to allow vSan to send data to devices without contention.

One other cool feature is that it also removes the need for disk groups making maintenance (adding or removing of drives) and recover after failure much easier. It also eliminates failure domains.

Source: VMware

Native vSAN Snaphots

With vSAN ESA 8 there is finally a massive change to the way Snapshots are made. Snapshots can now be created more efficiently and are more scalable without performance impact on running VM’s. This is done by creating Point-in-Time states of data fast and efficiently.

This new native Snapshot solution is integrated in vSphere and will also be available for 3rd party VADP backup solutions.

Important improvements:

  • Consistant, low impact
  • Fast consolodation
  • Low stun times

Adaptive RAID-5

A new adaptive RAID-5 configuration is introduced in vSphere 8, or actually 2 configurations. Lets see what this new adaptive RAID-5 brings us shall we?

Improved space efficiency in smaller clusters:

  • 4+1 schemE using 1.25x capacity for resilient data storage
  • 1+1 schemE using 1.5x capacity for resilient data storage

Automatically adjusting RAID-5 scheme to accommodate cluster size

  • 4+1 scheme used for 6 hosts or more
  • 2+1 scheme used for 3 to 5 hosts

These new configurations allow administrators of smaller clusters more freedom of choice using less hosts to achieve the same resiliency as larger clusters.

vSAN 8 Original Storage Architecture improvements

Not only is there the introduction of vSAN ESA but there is also an improvement made in vSAN OSA.
Introducing a new logical buffer limit, almost trippeling the current one. The buffer capacity can now range form 600 GB to 1.6 TB. This will allow for improved performance and constancy for vSAN OSA users. The extra capacity offers higher performance rates for a longer period of time.

Final thoughts

There you have it, New and improved vSAN 8 explained or at least part of the improvements. As always I hope you enjoyed reading this blog and if you want to know more please head over to VMware and dig into vSAN 8 here.

I hope you come back soon to browse to our other blogs as well here on


By Arjen Kloosterman

Sr. Solutions Engineer @ Netapp

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