vSAN backup restore.

[mutthu]

We have a 2-node vSAN cluster running version 6.7. Each node has 1 CPU, and the vSAN OS is installed on an SD card. I want to upgrade the OS, but it's not recommended to do so on the SD card. Instead, I'm going to add an HDD and install the OS on it. The hard drive cannot be configured to be in RAID to protect the OS since there is only one bay. In the worst-case scenario, I will have to rebuild the node if the OS HDD fails. Is it possible to backup the configuration from the other node and restore it since both nodes have similar hardware? If so, can someone provide the steps?

[TheBobkin]

@mutthu, I wouldn't advise anything like copying the data off one ESXi install to another as this will break some thing like them having the same host/node UUID and vDS UUIDs.

Do you have or can temporarily have vSphere Enterprise license here so you can just use Host Profiles instead?

[depping]

you could always upgrade to SD, it is supported, but it would be recommended to offload the OS Data.

[pkvmw]

Just my 2 cents here:

You could backup the vSAN configuration before the host fails (e.g. after every configuration change manually, or periodically automated via PowerShell script or whatsoever). When one of your hosts fail, you need to install the same build version the configuration backup was taken on and then you can restore the backup.

See here: https://kb.vmware.com/s/article/2042141. So backing up all hosts is as easy as:
$ Get-VMHost | Get-VMHostFirmware -BackupConfiguration -DestinationPath C:\Downloads\
(or Get-Cluster -Name "MainCluster" | Get-VMHost | Get-VMHostFirmware [...] - if I recall correct)

Also noteworthy, when it comes to vSAN is that it does recognize the vSAN disks automatically after re-installing the host. The data on the vSAN diskgroups is not lost, as long as the disks stay healthy. So you "only" need to re-do your basic ESXi configuration like networking settings.