Engineer Tang's Implementation Study Notes

Jul 21, 2026 · Operations

Disk Full but du Shows Less? Hidden Deleted Files Held Open by Processes

When df reports 98% disk usage but du accounts for only 50%, the missing space is typically held by a process that deleted a file but kept its file descriptor open; this article demonstrates how to locate the offending process with lsof, reclaim space instantly via /proc/pid/fd, and prevent recurrence by truncating logs instead of removing them.