Quick Fix – Found zero ssd devices for SSD cache tier

VCF, vSAN, , , , ,

When i added a host to an existing vSAN cluster via the SDDC manager the task failed with the following error: “Found zero ssd devices for SSD cache tier”

To quickly fix this we need to set the cache disk on the ESXi host to SSD, you can check the current value with the vdq -q command. As you can see in the picture below the disk I want to use for the cache is marked with a value of “0”, so it is not recognized as SSD drive.

In the past you had to set the the disk to SSD with SATP claim rules, but from version 7.x and 8.x there is a new and simpler command to do this. Run the following ESXCLI command and use the storage device ID and the -M option with value of true (or false to revert the change) to mark the device as an SSD.

esxcli storage hpp device set -d naa.6000c299027de72c68de829e23455e88 -M true

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VCF 5.0 – Remove vSAN datastore after VCF deployment failed

VCF, , , , ,

After a failed deployment of VCF 5.0, i was left with a vSAN Datastore on the first host in the cluster, and this was blocking a retry of the deployment.

In this state the vsanDatastore is unable to be deleted. If I try to delete it, the option is greyed out.

To delete the datastore and the partitions of the disks, we first need to SSH into the host and get the cluster.

We need the Sub-Cluster Master UUID, copy it to the clipboard. To leave the cluster the command is:

esxcli vsan cluster leave -u <Sub-Cluster Master UUID>

The ESXi UI now shows that the datastore is gone.

Let’s check the cli, if there still is a vSAN cluster or storage:

esxcli vsan cluster list
esxcli vsan storage list

No vSAN clusters or storage is configured on the host, after this the retry was successfully and the VCF management cluster was deployed.

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vSAN 7.0 Resync Throttling

vSAN, , ,

When we upgraded to vSAN 7, immediately we faced an annoying error message in Skyline health which complained about the Resync Throttling.

This setting is deprecated since 6.7 and can only be set via Powercli, below a few lines of code to set the value to 0 to all Hosts in the cluster. When the VSAN Host is patched or sometimes we even see the warning again after a reboot. Just run the script again and the warning is gone. 

$vc="yourVC"
Connect-VIServer $vc<br>$hosts = Get-VMHost
foreach($esx in $hosts){
Write-Host "Displaying and Updating VSAN ResyncThrottle value on $esx" 
Get-AdvancedSetting -Entity $esx -Name VSAN.DomCompResyncThrottle | Set-AdvancedSetting -Value 0 -confirm:$falseGet-AdvancedSetting -Entity $esx -Name VSAN.DomCompResyncThrottle
}

Please run scripts at your own risk! If you are not comfortable please contact VMware Support.

You can also check this KB article for another solution regarding the resync Throttling

https://kb.vmware.com/s/article/83742

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