Problem

The Memory Information under Administration > System > System Info displays 0% Free MetaSpace:

Environment

• JIRA applications running with Java 1.8 or later.
• The -XX:MaxMetaspaceSize JVM argument is not configured.

Cause

This is the expected behavior.

Java 8 replaces the PermGen memory area with MetaSpace, which is dynamically allocated on native memory. The amount of native memory that can be used for class metadata is by default unlimited and managed by the JVM automatically.

Source: 

• Java Platform, Standard Edition HotSpot Virtual Machine Garbage Collection Tuning Guide

Resolution

No action is required - This is the expected behavior.