A staging environment is specifically designed to be a near-replica of the production

environment. It's used for final testing of code, updates, and major system upgrades

before they are deployed to production. This environment often utilizes a sanitized or

anonymized subset of actual customer data to ensure testing is realistic and to

assess the impact of changes accurately. Furthermore, its production-like nature makes

it suitable for demonstrating new system features to stakeholders or for user

acceptance testing (UAT) in a controlled setting that mirrors the live system without

affecting actual users or data.

· A. Development: This environment is used by developers to build and unit test code.

It typically uses mock data or very limited, often synthetic, datasets, not a

representative subset of customer data, and is not stable enough for impact assessment

of major upgrades or feature demonstrations to external stakeholders.

· B. Test: While used for quality assurance and finding defects, a test environment

may not always use a subset of actual customer data (often uses specifically crafted

test data) and is primarily focused on verification and validation rather than a final

pre-production impact assessment or feature showcase in a production-like replica.

· C. Production: This is the live environment used by actual customers with real-time

data. It is not used for assessing impacts of major upgrades prior to their validation or

for demonstrating potentially unstable features due to the risk of service disruption and

data integrity issues.

1. Microsoft, Azure, "Deployment Staging environments":

o URL: https://learn.microsoft.com/en-us/azure/app-service/deploy-staging-slots

o Relevant Information: While specific to Azure App Service, the concept of a staging

slot (environment) is for deploying and testing changes before swapping to production.

"Deployment slots let you deploy different versions of your app to different URLs. You

can use slots for staging new features, A/B testing, or maintaining a production version

while working on a new one...After you validate your changes in a staging slot, you can

swap the staging slot with the production slot." This supports the idea of final validation

before go-live, implicitly including assessing impacts and potentially demonstrating

features. The use of "production data" in staging (often a sanitized subset) is a common

best practice for accurate testing.

2. AWS, "Workload hosting > Environments":

o URL: https://docs.aws.amazon.com/wellarchitected/latest/workloadhosting/environments.html

o Relevant Information: This document discusses different environments. While not

explicitly detailing "subset of customer data" for staging, it describes staging (or pre-

production) as an environment that "should be as identical as possible to the

production environment" and is used "to test the software before it is released to the

production environment." This identical nature is key for assessing upgrade impacts

and makes it suitable for demonstrations.

3. Atlassian, "Deployment environments: Development, staging, production,

and testing":

o URL: https://www.atlassian.com/continuous-delivery/principles/deploymentenvironments

o Relevant Information: "A staging environment (stage) is a near-replica of a production

environment... Staging environments are used to test and catch any code issues before

they are deployed to a production environment. This environment should be as similar

to production as possible, which can help to test for performance, data integrity, and

usability... It can also be used for demonstrations, training, or user acceptance testing

(UAT)." This directly supports using staging for testing major changes, demonstrating

features, and often implies the use of production-like data (a subset).

4. University of Washington, "Environments - Test, Staging, Production":

o URL: https://www.washington.edu/cac/ fauc/ISDOC/Projects/devenviron.html (Note:

The direct link might be subject to change over time, searching for "University of

Washington software development environments" might be needed). A more stable

similar resource: University of Michigan, "Development, Staging, and Production

Environments":

o URL: https://safecomputing.umich.edu/protect-the-u/protect-yourunit/information-security-guidelines-and-procedures/development-staging-and-

production-environments

o Relevant Information: "The staging environment serves as a model of the production

environment... Testing in this environment should focus on integration with other

production or production-like systems... The staging environment is also often used for

demonstrations and training on new features as it closely resembles the production

environment without being the live system." This again highlights its role in

demonstrations and testing major changes with production-like data.