When Virtual SAN is enabled in the manual mode for the host cluster, you can use a manual method of combing specific SSDs with specific HDDs and creating user-defined disk groups on a particular host.
When you create a disk group, your main consideration should be the ratio of SSD to HDD capacity. Although the ratios depend on use cases and workloads, the best practice is to use 1:10 ratio of the SSD to HDD capacity.
- Browse to the Virtual SAN cluster in the vSphere Web Client navigator.
- Click the Manage tab and click Settings.
- Under Virtual SAN, click Disk Management.
- Click the Create a new disk group icon.
- Select an SSD disk, and then select one or multiple non-SSD disks.
For each disk group, you can select only one SSD and up to six non-SSD disks.
- Click OK.
The new disk group appears on the list.