Knowing when something is down.
WHAT TO MONITOR
Whether your site responds Whether mail is accepted Whether key services answer
WHY EXTERNAL MONITORING
You do not notice an outage at night, or while working.
WHAT A MONITORING SERVICE DOES
Checks from outside, at intervals, and alerts you.
WHAT TO CONFIGURE
Checks from more than one location, if offered Alerts to somewhere you will see them A sensible interval
THE ALERT DESTINATION
Not an address on the affected domain.
If mail fails, the alert about it fails too.
WHAT ELSE TO MONITOR
Certificate expiry Domain expiry Disk and resource usage
THOSE THREE
Cause outages that are entirely preventable.
WHAT TO AVOID
Alerts so frequent that people ignore them.
WHAT TO DO WITH AN ALERT
Verify independently before acting.
Monitoring services produce false alerts.
WHAT TO RECORD
Outages and their causes, so patterns emerge.
