Things to keep in mind while working in the production environment

Do's and Don'ts

Don'ts	Do's
Do not restart the servers during business hours.	Always restart the servers after business hours/outside the business or during the downtime.
Do not patch all the same node at the same in the cluster servers (SQL/Application Cluster).	Always patch the node one by one in the cluster server.
Do not patch the passive node first in the cluster.	Always Patch the active node first and check the service status before proceeding further to the passive node.
Do not make changes in the Production environment without a CR (change record).	Always raise incident and raise a CR with the incident reference to make changes in the Prod environment (Retro or Emergency change).
Do not check or investigate an issue in Production environment without an incident.	Always log an incident to investigate an issue.
Do not use open-source software in the Enterprise environment.	Always use licenced software in the Enterprise environment.
Do not host an application database in the application server in the Enterprise environment.	Always host the database in the separate server in the Enterprise environment.
Do use “SQL Server Express” software in the Enterprise environment.	Always use “SQL Enterprise” software in the Enterprise environment.
Do not proceed with major prod activity without knowing the RTO(Recovery Time Objective)/RPO of the application.	Always check the RTO/RPO(Recovery point objective) of the application before performing any major activity.
Do not proceed with any changes in prod environment without implementing in lower environment(RND/UAT/PERF).	Always implement the changes in the lower environment to check application stability and performance before applying in Prod environment.
Do not proceed with a change without backup plan.	Always have "Rollback plan and Rollback time" for an Change activity.