Who a file belongs to.
WHAT OWNERSHIP IS
Every file belongs to a user and a group.
WHY IT MATTERS
Permissions are applied relative to the owner.
A file the web server cannot write to will not be writable regardless of permission numbers if ownership is wrong.
WHEN IT GOES WRONG
After uploading files as a different user After restoring a backup incorrectly After a migration After running a script as the wrong user
THE SYMPTOM
Uploads failing, updates failing, or a site unable to write cache or log files.
Frequently misdiagnosed as a permissions problem.
WHAT TO DO
On shared hosting, ownership is usually handled automatically.
If it is wrong after a manual operation, open a ticket.
WHAT NOT TO DO
Set permissions to 777 to work around an ownership problem.
That makes files world-writable to solve a problem that was not about permissions.
HOW TO CHECK
File Manager shows ownership alongside permissions.
