Tessell charges customers based on the total size of the Availability Machine in GiB each month. The database snapshots and archive logs managed by an Availability Machine constitute its size. Tessell does not charge customers for Availability Machines of sizes less than 150% of database storage.

Let us take a real-world example. A data owner at Acme Corp creates a 500 GiB database service called ‘CRMDB’ with Tessell. While the service instances will be metered every hour, Tessell will not charge for this Availability Machine’s storage until it exceeds 750 GiB-month (or 750 * 730 = 547,500 GiB-hours during a month). Over time, this Availability Machine captures and maintains database snapshots and logs to facilitate recovery. Let us say, after a couple of weeks, the cumulative size of these snapshots exceeds 750 GiB per month. Tessell will then bill the customer for any excess storage consumed by the Availability Machine. In this example, if the Availability Machine size stays below 750 GiB-month (or a total sum of 547,500 GiB metered every hour through the entire month), the Availability Machine’s cost to the customer is $0. Also, it is important to note that both regular and sanitized snapshots contribute towards the size of an Availability Machine.