Alternative PHP Cache

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User Contributed Notes 3 notes

umut dot kirgoz at gmail dot com
2 years ago
Since APC 3.1.3, there is a bug (http://pecl.php.net/bugs/bug.php?id=16814) which produces warnings like "Potential Cache Slam Averted for Key" when slam defense is on and you're trying to write a key that already exists.

These is not a fix right now for this, but you can change the APC settings from php.ini file like below if possible:

apc.write_lock = 1
apc.slam_defense = 0
mike at eastghost dot com
2 years ago
Was using Memcache and Memcached extensions, painfully bouncing between faults, failures and shortcomings of each.  My two cents: Neither of these old drivers has been a smash hit, repressing and slowly dooming of the true potential and full use of unix memcached.

The pain finally drove to me to try APC's apc_store and apc_fetch.  The results?  Instant success, no more errors, an order of magnitude (at least) speed boost, plus one less thing (memcached) to run.  Nice.  Never going back again.  Thank y'all.
hello at haroonahmad dot co dot uk
5 years ago
Disclaimer: i do not guarantee it will work for you so you better use it at your own risk. It works for me.

* I am using # symbol for all shell commands

I am posting a quick step-by-step guide to install APC on servers (dedicated or VPS) with cpanel/whm working.

First login as a root to your server/vps and make a directory to work with this plugin,

#mkdir /home/APC-php

#cd /home/APC-php

now here we will first download the APC with following command

#wget http://pecl.php.net/get/APC-3.0.14.tgz

you can check for the latest version

now you can use gzip and tar separately or tar -xzvf to unzip this file

#tar -xzvf APC-3.0.14.tgz

now you will have a APC-3.0.14 folder.

#cd APC-3.0.14

now you have to make php configuration files by following command


after this use following three commands

# ./configure --enable-apc --enable-apc-mmap --with-apxs --with-php-config=/usr/bin/php-config

*if you do not know the php path then execute ( which php ) command it will display the path. on a typical cpanel vps it could be /usr/bin/php-config or /usr/local/bin/php-config but you better check it before executing the above command)


#make test

#make install

NOTE: if you are using suPHP then skip --with-apxs

*one more thing, if you use

#make test

command it shows 3 tests failed then do not worry, it showed at least to me but worked with the final steps.

the (make install) command will return the apc.so module path, note down that with you as you will have to feed it in the php.ini file in the next step.

check your php.ini location by

#php -i | grep php.ini

then open it with your favorite editor. mine was at

#vi /usr/local/lib/php.ini

and go to the last line and paste the following


now there is a catch in it, if you have other modules installed and their extension directory is different than the one MAKE INSTALL showed for APC so you have to move your apc.so to that directory so that all modules are in the same directory. in my case my APC directory was


but i moved apc.so from this location to my other location where my other extensions.so files were.

you can check that path in php.ini sectiion of

extension_dir = ""

after this restart your apache, for different servers it may vary mine worked with

#service httpd restart

if everything works fine it will restart apache without showing any error. in case of any error, roll back your php.ini changes and restart apache and discuss your problem in some forum or email me at hello@haroonahmad.co.uk

now check the phpinfo() output in your browser and it will display APC version information etc. for command line you might do

php -i | grep apc

I hope it helps.

Haroon Ahmad
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