Swap usage high
Swap usage at or above 50%. Swap I/O is 10-100x slower than RAM; sustained swap = thrashing. Critical band (>=80%) indicates imminent service degradation.
Remediation
When this rule fires on one of your servers, the dashboard alert detail page renders the full remediation guidance: the command to run, what to verify after, and Furnace's annotation for your specific distro + hardware. Sign in at app.glassmkr.com to see the live alert.