Check your virtual machine capacity total and check your storage policy. Workout how much capacity you require for vSAN. vSAN will slow down once it reaches about 70%.
In my lab I was only able to remove one disk at a time without an error.
In my lab I did this without putting the host in maintenance mode, no outage to virtual machines
Check your capacity in vCenter and take note
Check how many disks you have in disk management
Take note of the disk being removed and ensure it is the vSAN capacity disk
Check unclaimed disks (once you remove the capacity disk you will have an extra disk available)
Check disk space in SDDC Manager for workload make sure it matches vcenter
