In this post, we recap Getting More Out of vSAN Session 2: Server & Network Hardware Design Guide. Getting More Out of vSAN is an ongoing technical webcast series led by vSAN experts. The webcasts are unique because of the interactive, live Q&A session at the end, where you can provide feedback and get your questions answered live by the vSAN product team!

After each session airs, we will share a high-level recap including the top five questions and answers, right here on Virtual Blocks. If you have 60 minutes to spare, we also highly recommend that you watch the webcasts on-demand.


Session 2: Server & Network Hardware Design Guide

With HCI bringing more modern hardware than the most advanced storage systems, it is important to get the most out of your HCI solution. In this session, John Nicholson, Senior Technical Marketing Architect and Rakesh Radhakrishnan, Group Product Manager, outline the best practices for hardware and network design to get the most out of vSAN.

For server hardware, they discuss hardware selection and sizing guidelines including best practices for selecting IO controllers, boot devices, flash devices and magnetic drives.

The networking section begins with an overview of vSAN and ESX networking concepts, touching upon vSphere standard and distributed switches, then goes on to discuss best practices around assigning network shares for management, vMotion vSAN traffic etc.

The webcast concludes with an overview of vSAN health checks and upcoming features to support firmware and driver updates.


Top Five Questions and Answers from Session 2:


Q1. What are some of the key design considerations for vSAN?


Ensure that all the hardware used in the design is supported by checking the VMware Compatibility Guide (VCG).

Make sure that all software, driver and firmware versions used in the design are supported by checking the VCG.

Ensure that the latest vSphere patch/update level is used when doing a new deployment, and consider updating existing deployments to the latest patch versions to address known issues that have been fixed.

Design for availability. Consider designing with more than three hosts and additional capacity that enable the cluster to automatically remediate in the event of a failure.

Design for growth. Consider initial deployment with capacity in the cluster for future virtual machine deployments, as well as enough flash cache to accommodate future capacity growth

See more details on design and sizing.


Q2. What types of virtual switches does vSAN support? Is vSphere Distributed Switch included with vSAN?

A: vSAN supports both vSphere Standard Switches (VSS) and vSphere Distributed Switches (VDS). VMware vSAN includes VDS licensing. We recommend the use of vSphere Distributed Switches in order to realize network QoS benefits offered by vSphere NIOC.

View more about switches.


Q3. Do you recommend stacked or redundant switches for vSAN traffic?

A: To ensure high availability and to avoid single points of failure, vSAN network should have redundancy in both the physical and virtual network paths and components. Switches can fail, crash or may require firmware updates and reboots. Redundant switches can help ensure availability in these instances.


Q4. Is it possible to monitor the status of SSD drives used for vSAN and have vSAN alert you when disks are wearing out and/or prone to fail?

A: vSAN monitors SSD and MD health and proactively isolates unhealthy devices by unmounting them. It detects gradual failure of a vSAN disk and isolates the device before congestion builds up within the affected host and the entire vSAN cluster.

More information on vSAN Disk Monitoring and Proactive Health Analysis.


Q5: If we base a vSAN design around a ready node configuration, can we swap out drives to another type that is still on the HCL?

A: If you substitute the ready node drives with the same class of drives i.e., same or higher endurance and performance class for SSD and same or higher RPM and access protocol for HDD, you should not have any issues.


Missed the recap of Getting More Out if vSAN Session 1: vSAN Architecture & What’s New in 6.5? Read the blog.