Why does df show no space, but du shows that space should be available?

The df command shows free space at the filesystem level, while du shows the size of files and directories visible in the current directory.

Reasons why df might show no free space, but du shows available space:

• Deleted but open files: If a file was deleted from the directory but a process still has it open, du will not see it, but df will account for the space used.
• Files outside the visible directory: du only counts the specified directory, while df considers the entire filesystem.
• Hidden or mounted directories: If there are mount points or hidden files, du might not include them.

Example: if a process writes to a log that was later deleted, the space for that file won't be freed until the process closes the descriptor.

To find such files, you can use lsof:

lsof +L1

This will show open deleted files that are occupying space.