I have a problem that I cannot resolve.
All PHP sessions are stored in the directory /var/lib/php5/sessions/ and session files are stored there.
But completely randomly I see the following error: Failed to write session data (files). It happens 1 - 2 times per day that is it happens for 1-2 sessions per day. All the rest sessions are ok. And the files are also promptly.
To me it seems that sometimes PHP cannot write to the folder or (?) is it maybe the cause that file with the same name already exists.
What is the cause? How to prevent this?