APC
APC is a great operation code caching system for PHP that can help speed up your site.
Install APC
To install APC, execute the following command:
sudo apt-get install php-apc
php.ini configuration
Edit the php.ini
file:
sudo vi /etc/php5/apache2/php.ini
And add the following code:
[APC] apc.enabled=1 apc.shm_segments=1 ;32M per WordPress install apc.shm_size=128M ;Relative to the number of cached files (you may need to watch your stats for a day or two to find out a good number) apc.num_files_hint=7000 ;Relative to the size of WordPress apc.user_entries_hint=4096 ;The number of seconds a cache entry is allowed to idle in a slot before APC dumps the cache apc.ttl=7200 apc.user_ttl=7200 apc.gc_ttl=3600 ;Setting this to 0 will give you the best performance, as APC will ;not have to check the IO for changes. However, you must clear ;the APC cache to recompile already cached files. If you are still ;developing, updating your site daily in WP-ADMIN, and running W3TC ;set this to 1 apc.stat=1 ;This MUST be 0, WP can have errors otherwise! apc.include_once_override=0 ;Only set to 1 while debugging apc.enable_cli=0 ;Allow 2 seconds after a file is created before it is cached to prevent users from seeing half-written/weird pages apc.file_update_protection=2 ;Leave at 2M or lower. WordPress doesn't have any file sizes close to 2M apc.max_file_size=2M ;Ignore files apc.filters = "/var/www/apc.php" apc.cache_by_default=1 apc.use_request_time=1 apc.slam_defense=0 apc.mmap_file_mask=/tmp/apc.XXXXXX apc.stat_ctime=0 apc.canonicalize=1 apc.write_lock=1 apc.report_autofilter=0 apc.rfc1867=0 apc.rfc1867_prefix =upload_ apc.rfc1867_name=APC_UPLOAD_PROGRESS apc.rfc1867_freq=0 apc.rfc1867_ttl=3600 apc.lazy_classes=0 apc.lazy_functions=0
source: http://gregrickaby.com/the-perfect-apc-configuration/
For more information about APC configuration, please read: http://www.php.net/manual/en/apc.configuration.php
Test APC
To see if APC is enabled and running, create a php file called info.php
in your apache2 root folder and the following code:
<?php phpinfo();
And go to your website and check if you see the APC module