vSAN is the VMware software defined solution that allows you to manage compute and storage with a single platform, and offers the main benefit of deploying production ready vSphere clusters without having to use shared storage. In my vSphere home labs in nested environment, I used to deploy an iSCSI Storage server to make shared storage available to my ESXi hosts. If you use vSAN, shared storage is not a must to deploy your cluster and enable common vSphere features like HA, DRS, Storage DRS, …etc. This make things easier by just enabling the vSAN feature in the cluster, assuming all prerequisites are met.
vSAN can have two types of deployments:
- Hybrid vSAN: should contain one Flash device for the Cache Tier and one or more Magnetic disk for the Capacity Tier.
- All-Flash vSAN: should contain one Flash device for the Cache Tier and one or more Flash disk the Capacity Tier.
In hybrid deployments where you have a combination of SSD and HDD drives, vSAN needs at least one SSD disk for caching, so in either type of vSAN deployment, your ESXi hosts participating in the vSAN cluster will need to have least one SSD drive .
In case of a nested lab, your ESXi hosts are actually virtual machines, If your host virtualization server contains only HDD backed storage, there’s a nifty trick you can use to emulate an SSD hard drive when creating a virtual machine. In the ESXi configuration file, just add the line scsi0:1.virtualSSD = “1” on the disk you want have as SSD. In my lab, I have three disks for each nested ESXi hosts. One for the ESXi installation, one caching disk (10GB) and one capacity disk (50GB).
I want to convert the second disk to SSD. The id for this disk is scsci0:1 in the vmx configuration file.
Supposing that the host is already added to vCenter, shut down the ESXi VM and simply add scsi0:1.virtualSSD = “1” as shown below.
Start the ESXi VM and go the host “Storage Devices” settings to check that the new setting has been applied.
There you go! You have now vSAN ready node for your vSAN nested lab deployments.