HOW TO: Install PECL APC Cache on CentOS
The Alternative PHP Cache (APC) is an op-code pre-compiler and a cache system that can boost the performance of a PHP application up to 10 times. Op-code caches are very effective for a Drupal website, since Drupal deals with large number of source files and time spent in parsing them significantly affects performance. However, if you don’t have XAMPP and need to install it on CentOS, you can follow this to get around some of the problems that happen with the default server settings. h2. Install Pre-reqs Using yum install the required prerequisites.
sudo yum install php-devel php-pear httpd-develInstall APC
Use the command
sudo pecl install apc at this point you’ll likely see the error
Fatal error: Allowed memory size of 8388608 bytes exhausted (tried to allocate 92160 bytes) in /usr/share/pear/PEAR/PackageFile/v2/Validator.php on line 1831 Apparantly, the PECL/PEAR scripts do not use the settings from /etc/php.ini so you need to update PEAR’s memory settings to give is some more breathing room. Edit the file /usr/share/pear/pearcmd.php and add the following at the beginning:
@ini_set('memory_limit', '16M');Configure/Restart
Now configure PHP to use the new extension. Create the file /etc/php.d/apc.ini and in that file put:
extension=apc.soNow restart apache
sudo /etc/init.d/httpd gracefulMaintenance
In the future, if new versions of APC are released, you can easily upgrade them using
sudo pecl upgrade apc
Ipconfig
Ipconfig
Syntax
Parameters
/all : Displays the full TCP/IP configuration for all adapters. Without this parameter, ipconfig displays only the IP address, subnet mask, and default gateway values for each adapter. Adapters can represent physical interfaces, such as installed network adapters, or logical interfaces, such as dial-up connections.
/renew [ Adapter ] : Renews DHCP configuration for all adapters (if an adapter is not specified) or for a specific adapter if the Adapter parameter is included. This parameter is available only on computers with adapters that are configured to obtain an IP address automatically. To specify an adapter name, type the adapter name that appears when you use ipconfig without parameters.
/release [ Adapter ] : Sends a DHCPRELEASE message to the DHCP server to release the current DHCP configuration and discard the IP address configuration for either all adapters (if an adapter is not specified) or for a specific adapter if the Adapter parameter is included. This parameter disables TCP/IP for adapters configured to obtain an IP address automatically. To specify an adapter name, type the adapter name that appears when you use ipconfig without parameters.
/flushdns : Flushes and resets the contents of the DNS client resolver cache. During DNS troubleshooting, you can use this procedure to discard negative cache entries from the cache, as well as any other entries that have been added dynamically.
/displaydns : Displays the contents of the DNS client resolver cache, which includes both entries preloaded from the local Hosts file and any recently obtained resource records for name queries resolved by the computer. The DNS Client service uses this information to resolve frequently queried names quickly, before querying its configured DNS servers.
/registerdns : Initiates manual dynamic registration for the DNS names and IP addresses that are configured at a computer. You can use this parameter to troubleshoot a failed DNS name registration or resolve a dynamic update problem between a client and the DNS server without rebooting the client computer. The DNS settings in the advanced properties of the TCP/IP protocol determine which names are registered in DNS.
/showclassid Adapter : Displays the DHCP class ID for a specified adapter. To see the DHCP class ID for all adapters, use the asterisk (*) wildcard character in place of Adapter. This parameter is available only on computers with adapters that are configured to obtain an IP address automatically.
/setclassid Adapter [ ClassID ] : Configures the DHCP class ID for a specified adapter. To set the DHCP class ID for all adapters, use the asterisk (*) wildcard character in place of Adapter. This parameter is available only on computers with adapters that are configured to obtain an IP address automatically. If a DHCP class ID is not specified, the current class ID is removed.
To display the basic TCP/IP configuration for all adapters, type:
ipconfig
To display the full TCP/IP configuration for all adapters, type:
ipconfig /all
To renew a DHCP-assigned IP address configuration for only the Local Area Connection adapter, type:
ipconfig /renew “Local Area Connection”
To flush the DNS resolver cache when troubleshooting DNS name resolution problems, type:
ipconfig /flushdns
To display the DHCP class ID for all adapters with names that start with Local, type:
ipconfig /showclassid Local*
To set the DHCP class ID for the Local Area Connection adapter to TEST, type:
ipconfig /setclassid “Local Area Connection” TEST