When you install additional physical disks on ESXi hosts, you can create an independent RAID set with these disks.
With this approach, you do not need to replace the cluster member. Instead, you add the new RAID as an extent to your host's local VMFS datastore. You can then expand the VSA cluster after it detects additional storage capacity.
This method preserves on disk data.
The entire workflow includes these tasks.
Place the VSA cluster into maintenance mode. See Perform Maintenance Tasks on the Entire VSA Cluster.
Power off the ESXi host to reconfigure.
Install new storage disks and create a new RAID set using the disks. See Reconfigure Storage on an ESXi Host.
The new RAID appears on the host as a new storage device that you can add as an extent to the host's local VMFS datastore.
Increase the capacity of the host's VMFS datastore by adding the new extent. See Increase VMFS Datastore Capacity in the vSphere Web Client.
Exit VSA maintenance mode.
Expand the VSA cluster. See Increase VSA Cluster Storage Capacity.