Why does a message about insufficient disk space appear when creating a file despite available free space?

A message about insufficient disk space despite available free space can occur for several reasons:

• Inode limit. In file systems, besides storage space, there is a limit on the number of files (inodes). If all inodes are used up, creating a new file is impossible even if there is free space.
• User quotas. On some systems, administrators can set limits on disk space usage or the number of files for specific users.
• Access rights issues. If a user does not have write permissions to a directory, the system may display an error similar to "no space".
• Mounting peculiarities. For example, if a directory is mounted with restrictions or on another partition with less free space.

To diagnose, check the number of free inodes with the command df -i and user quotas (quota), as well as access rights to the directory.