When using VMware Tanzu for Postgres on Tanzu Platform 10.1 and below, each Postgres Database Service Instance (deployed as high availability) will have 5 VMs be default. Those being ETCD and Postgres VMs.
By default, the tile configuration uses the same VM size for both of these VM types. This may not be optimal, as you may want your Postgres VM to have a larger VM/Disk type than your ETCD.
VMware Tanzu for Postgres on Tanzu Platform 10.1
This has been addressed in Tanzu for Postgres on Tanzu Platform 10.2. Starting in this release, HA instances have been consolidated into a single 3-node setup, where both etcd and Postgres run on as process on each node.
This means that only one VM type needs to be configured for the instance, as opposed to two.