You can remove hosts from your SDDC as long as the number of hosts in your SDDC cluster remains above the minimum required by vSAN storage policies.
Both conventional (single-AZ) and stretched clusters require at least two hosts. A stretched cluster that has been scaled out to four or six hosts cannot be scaled in. Stretched clusters with more than six hosts can be scaled both out and in.
VMware Cloud on AWS clusters require a minimum of three active hosts with an additional spare host.
Whenever you reduce cluster size, storage latency increases due to process overhead introduced by host removal. The duration of this overhead varies with the amount of data involved. It can take as little as an hour, though an extreme case could require more than 48 hours. While cluster-size reduction (scale-in) is underway, workload VMs supported by the affected clusters can experience significant increases in storage latency.
When you remove a host, VMs running on that host are evacuated to other hosts in the SDDC cluster. The host is placed into maintenance mode and then removed.
Ensure that you have sufficient capacity in your cluster to hold the workload VMs that will be evacuated from the hosts that you remove.
- Log in to the VMware Cloud Console at https://vmc.vmware.com.
- Click on your SDDC and then click Summary.
- If the SDDC has only one cluster, select from the SDDC card.
- If the SDDC has more than one cluster, select from the card for the cluster from which you want to remove the hosts.
- Select the number of hosts you want to remove.
If you are removing hosts from a multiple availability zone cluster, you must remove them in multiples of two.Note:
All vSAN storage policies have requirements for a minimum number of hosts. If you attempt to reduce the number of hosts below this minimum, the operation fails. See vSAN Policies.
- Select the I understand that this action cannot be undone check box.
- Click Remove.
This action initiates the host removal process. A host slated for removal transitions to the DELETING state while its data is being moved and billing for the host stops. It can take several hours to move large volumes of data. When the data move is complete, the host is removed from vCenter inventory.
- If you are removing a single host, VMware's billing for that host stops immediately.
- If you are removing multiple hosts, they are queued and removed one at a time to avoid violating vSAN storage policies. Billing for a host continues while it is queued for removal. After each queued host is removed, VMware Cloud on AWS verifies that removing the next host in the queue won’t violate vSAN storage policies. If that check fails, the host is not removed and VMware's billing continues. Otherwise, the host is removed.