I am having a strange problem, since i have upgraded PHP from 5.4 to 5.6. I have never seen the error myself, but the logs a full every day with this message:
session_write_close(): Failed to write session data (memcached). Please verify that the current setting of session.save_path is correct (127.0.0.1:11211)
This does no happens always, but only for certain users. And this happens on three different servers that have PHP ~5.6 & Memcached on latest Debian. I have tried switching Memcached extension to Memcache (of course with changing save_handler in php.ini), and the problem still persisted. I have also tried disabling session lock in php.ini. The problem is definitely related to PHP, because I have tested Memcached daemon itself with a Perl script, and there was not a single connection error.
Everything was working perfect for a very long time, and I started having this problem right after PHP upgrade, so it's not related with memcached config, or something like this. Maybe I am missing something? Maybe 5.6 requires some additional configs in its ini file? I just cant figure it out.
At the moment I am kind of stuck, and I hope anyone can help me with advice. I can try switching back to 5.4, or to 5.5, but that's not really an option, I would really like to stick to 5.6.