When troubleshooting a BIG-IP system where a partition is reported as full (100% utilization), identifying and removing large or unnecessary files is the immediate next step for restoration of system stability.

Symptoms of Full Partitions : If a file system (such as the root / or /var) becomes full, it can result in unpredictable system behavior, failure to save configurations, and the inability to log in to the Web UI.

The Root (/) Partition : This partition is intentionally kept small on F5 systems. It is highly sensitive to the storage of third-party software or diagnostic files that should ideally be stored in the /shared or /var directories.

Procedural Resolution : To resolve 100% disk usage, administrators should check for large files on the affected partition using CLI commands like du -ah or find / -xdev -type f -exec du {} \; | sort -rn | head -20.

Common Culprits : Large files typically causing these issues include old core files, tech support bundles, large diagnostic logs (packet diags), or temporary files created during administrative tasks.

Diagnostics vs. Remediation : While tests like the EUD (End User Diagnostics) or platform diagnostics are useful for hardware verification, they do not resolve file system exhaustion issues that have already reached a critical 100% state.