Since we moved to PHP 5.5 and it’s built in zend opcache, we decided to stop using APC.
Since zend opcache filled opcaching need only, we needed something for data-cache. There is one APC fork trying to extract data-caching code on Github. But we wanted something stable and mature so we choose to go with memcache.
I always hated presence of php5-memcache and php5-memcached – two solutions for similar needs. I read this and this and many more threads but could reach a conclusion.
Actually for our trivial needs both extensions should work fine. But we (forced) to choose php5-memcache as w3-total-cache doesn’t support only this!
Installation
apt-get install memcached php5-memcache service php5-fpm restart
Config
Increase Max Memory memcache can use
By default, its 64MB. You may need more.
- Open
/etc/memcached.conf - Look for value
-m 64 - Change it to
-m 1024 - Restart memcached
service memcached restart
Move PHP’s session storage to memcache
Open /etc/php5/mods-available/memcache.ini
Add following lines:
session.save_handler = memcache session.save_path = "tcp://localhost:11211"
Extra: Since memcached can works in multiserver mode, you can share session across server. Google for more info on this. I will post our config when we will write one! 😉
Changes in w3-total-cache plugin
In w3-total-cache plugin you need to choose memcache as backend for object-cache and database-cache.
Web-based Stats Viewer for Memcache
There are many but we choose phpmemcacheadmin
cd /var/www/example.com/htdocs/ mkdir mem && cd mem wget http://phpmemcacheadmin.googlecode.com/files/phpMemcachedAdmin-1.2.2-r262.tar.gz tar -xvzf phpMemcachedAdmin-1.2.2-r262.tar.gz chmod +r * chmod 0777 Config/Memcache.php
Hi, as soon as I set
session.save_handler = memcache(and restart php5) I get PHP Internal Server Errors all around… I cannot for the life of me figure out why ;(Can anyone share some tips on debugging this?
There are many things which can possibly go wrong. Please check error log for site.
I’m using also php5.5 with the zend optimiser. I’ve got issues each time I save the settings in W3TC. I think the setting page is cached by the zend optimiser (not by nginx) so the only way to see the changes is to force a browser refresh. Weird. Any way to force the zend optimiser to check the cache for each request? (like apc stat 0)
You may need following as described in https://rtcamp.com/wordpress-nginx/tutorials/php/zend-opcache/
Oups, missed these 2 lines. Thank you Rahul!
So, i use php 5.3…and want use memcached also
when i uncomment memcache.ini
session.save_handler = memcache
session.save_path = “tcp://127.0.0.1:11211”
my WP not work, blank page
memcached server is starting of course…and config to -l 127.0.0.1:11211
You can leave session related 2 lines commented.
Some bad plugins do not work with memcache-based sessions.
Have you considered the pros and cons of redis vs memcache?
Yes. It seems redis is faster but did not proper support for redis in wordpress & nginx world. So for now using memcache.
Also difference is too small to matter for WordPress/content sites.
Just to add that if installing all this you need to do service php5-fpm restart so w3-total cache will recognize the install
Thanks for comment. 🙂
I missed that. I have updated article so php will detect memcache module.
Hello!
When i’m trying connect to memcache-server using connect – all work very good. But when i trying use addServer – I all time see error timeout connect to server.
Can you help?
Sorry. I never developed any memcache related codes. We use memcache for WordPress sites through w3-total-cache plugin.
May be you can post it on – http://stackoverflow.com/
Hi, really like your posts about wordpress and nginx setup
how can I make sure I’m using memcache right?
I install the phpmemcacheadmin, but all the status is 0 ??
tks
Run
service memcached statusYou should see:
* memcached is runningAlso, make sure you have configured WordPress/W3-Total-Cache plugin to use database-cache/object-cache.