Dev and test Cosmos DB accounts replicated to more than one region

Every extra region repeats the throughput bill

Cosmos DB replicates data by adding regions to an account. Microsoft’s multi-region cost guide explains that the throughput configured for the account’s databases and containers is reserved in each associated region: with T RU/s provisioned and N regions, the account pays for T x N RU/s each hour. Storage is copied too. For production, that is the price of availability. For a development or test account created from a production template, it is a duplicate bill nobody needed.

Counting regions on your accounts

az cosmosdb list --query "[].{name:name, group:resourceGroup, regions:length(locations)}" -o table

az cosmosdb show --resource-group <rg> --name <account> \
  --query "locations[].{region:locationName, priority:failoverPriority}" -o table

How ZopNight decides an account is non-production

The account must carry a positive non-production signal. It is checked in this order:

1. A production environment tag (prod, production, prd or live on a key such as env, environment, stage or tier) is an absolute veto.
2. A dev or test environment tag (dev, development, test, testing, qa, stage, staging, sandbox, sbx) qualifies the account.
3. Otherwise the account name, then its resource group name, must contain dev, test, qa, staging, sandbox or demo. Names that look like infrastructure, such as devops, runner, agent, bastion or jumpbox, do not count.

The finding states which of these matched. A neutral name with no tags is not assumed to be non-production.

Accounts that get no finding

Beyond the non-production test, the account must be geo-replicated, its region count must be known and at least 2, and it must have a price. If the region count is not available, there is no finding rather than a guessed fraction. This check is about replicated regions, not about whether multi-region writes are turned on. Oversized throughput in a single region is covered by Azure Cosmos DB Provisioned Throughput Rightsizing.

Pricing a collapse to one region

saving = monthly cost x (regions - 1) / regions
cost after fix = monthly cost / regions

A two-region account saves half; a three-region account saves two thirds.

Removing the extra regions

1. Confirm with the owning team that the account is not production and needs no cross-region copy.
2. In the portal, open Replicate data globally and remove the extra regions, keeping the one the application uses.
3. Or update the location list so only one region remains: az cosmosdb update --resource-group <rg> --name <account> --locations regionName=<region> failoverPriority=0 isZoneRedundant=False.