Azure SQL Server is a logical container for SQL Databases and Elastic Pools. Most database and performance metrics are not exposed at the Server level, but each server does have a DTU Quota which limits the total amount of DTU that can be provisioned for all databases and elastic pools in the server. Blue Matador compares current DTU usage in a server to the current limit.
DTU stands for Database Transaction Unit. DTUs give you a way to compare database performance across the service tiers offered by Azure. DTUs roughly measure performance as a combination of CPU, Memory, Reads, and Writes. When provisioning compute for elastic pools, the acronym eDTU may be used to refer to DTUs that are part of an elastic pool.
Azure SQL enforces a DTU Quota on each SQL server to prevent potentially costly accidental expenditure. Blue Matador automatically checks current total server DTU usage and compares it to the limit so you can be warned when you are approaching the limit. Hitting the DTU limit will prevent further scaling actions that consume additional DTU. The limit can be raised from its default value of 55,000 DTU by opening a support ticket to request a limit increase.