Architecting a vCloud Availability for vCloud Director Solution : Billing
   
Billing
The service provider can use various mechanisms to charge tenants for vCloud Availability for vCloud Director usage.
Pay per protected VM
The simplest model aligns with VMware licensing. Protected VMs can be collected with the vCloud API and usage metering script. (See Section 4.11, vCloud Availability Metering.)
Pay per used storage
Cold storage–used for replicated data (base disks, MPIT snapshots) can be metered with vCloud API. (See Section 5.5.1, MPIT Storage Snapshots.)
Hot storage–used by (recovered) running VMs is reported as Org VDC allocated storage and can be metered via standard vCloud Director mechanisms.
Pay per used compute
A replication enabled Org VDC should be set to Pay-As-You-Go allocation model. After failover, allocated compute of running VMs is reported through standard vCloud Director metering mechanisms.
Pay per replicated network traffic
vCloud API (see Section 5.5.1, MPIT Storage Snapshots) can be used to collect how much data was transferred for each replication transfer. Note that this number does not include compression overhead and encryption efficiencies.