When something breaks.
THE ORDER
- Establish what is affected
- Contain, if something is actively causing harm
- Diagnose
- Fix
- Verify
- Record what happened
ESTABLISHING SCOPE
One site or all? The server itself or an application?
That determines where to look.
WHAT TO CHECK FIRST
Is the server responding at all Disk space Whether the relevant service is running The error log
THE DISK SPACE CHECK
A full disk causes a wide variety of confusing symptoms.
Check it early; it takes seconds.
IF THE SERVER IS UNREACHABLE
Console access through your provider, if available.
Know how to reach it before you need it.
IF YOU SUSPECT COMPROMISE
Different procedure. Preserve evidence, do not simply clean and continue.
RECORDING IT
What happened, what caused it, what you changed.
You will face the same problem again.