Linux Windows System Administrator Help

memcached is a high-performance memory object caching system intended to speed up dynamic web applications by alleviating database load.

memcached is meant to work in concert with something like the MySQL query cache, not replace it. The two implementations excel at vastly different things: memcached is an object cache, while MySQL provides a query cache.

memcached is extremely fast. It uses libevent, which provides a mechanism to execute a callback function when a specific event occurs on a file descriptor, to scale to any number of open connections. On a modern Linux system memcached utilizes epoll, is completely non-blocking for network I/O, ensures memory never gets fragmented, and uses its own slab allocator and hash table to achieve 0(1) virtual memory allocation.

How it install it on Linux server ?

• Install dependency software (Libevent)

#curl -O http://monkey.org/~provos/libevent-1.4.9-stable.tar.gz
#tar -xzvf libevent-1.4.9-stable.tar.gz
#cd libevent*
#./configure
#make
#make install

• Now let’s download the newest Memcached source

#curl -O http://www.danga.com/memcached/dist/memcached-1.3.0.tar.gz
#tar zxf memcached-1.3.0.tar.gz
#cd memcached-1.3.0
#./configure
#make
#make install

• Then add /usr/local/lib to LD_LIBRARY_PATH in your .bash_profile

LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
export LD_LIBRARY_PATH

How it Works

First, you start up the memcached daemon on as many spare machines as you have. The daemon has no configuration file, just a few command line options, only 3 or 4 of which you’ll likely use:

Run Memcached as a daemon (d = daemon, m = memory, u = user, l = IP to listen to, p = port)

#memcached -d -m 1024 -u root -l 127.0.0.1 -p 11211 –u nobody

This starts memcached as a daemon (-d) on the IP address and port specified with -l and -p, respectively, running as the user nobody (-u), allocating 1024  for object storage (-m). You should adjust the amount of storage to suit your needs; many memcached installs run with 4 GB. Once you are comfortable with your startup options, add the appropriate command to your startup scripts.

Create a /etc/init.d/memcached file and add above line to start memcached when the server boots

With memcached installed and running, it’s time to get PHP talking to the object cache. While multiple PHP API exists, the one in the PECL repository is recommended. If you are running a newer version of PHP, installation is as simple as:

# pecl install memcache

Or you can use following steps to install PECL memcache manually.

#cd /usr/local/src
#curl -O http://pecl.php.net/get/memcache
#tar zxvf memcache*
#cd memcache-*
#phpize
#./configure
#make && make install

Now we have to make sure PHP loads the newly built memcache.so library by adding the following line to php.ini:

extension=memcache.so

Now restart Apache:

Service httpd restart

Once it sucussfully install you can create phpinfo() on your webserver should now confirm that memcache is installed.

Regards
AlexP

301 redirect is the most efficient and Search Engine Friendly method for webpage redirection. It’s not that hard to implement and it should preserve your search engine rankings for that particular page. If you have to change file names or move pages around, it’s the safest option. The code “301? is interpreted as “moved permanently”.

IIS Redirect

• In internet services manager, right click on the file or folder you wish to redirect
• Select the radio titled “a redirection to a URL”.
• Enter the redirection page
• Check “The exact url entered above” and the “A permanent redirection for this resource”
• Click on ‘Apply’

ColdFusion Redirect

<.cfheader statuscode=”301? statustext=”Moved permanently”>
<.cfheader name=”Location” value=”http://www.new-url.com”>

PHP Redirect

<?
Header( “HTTP/1.1 301 Moved Permanently” );
Header( “Location: http://www.new-url.com” );
?>

ASP Redirect

<%@ Language=VBScript %>
<%
Response.Status=”301 Moved Permanently”;
Response.AddHeader(”Location”,”http://www.new-url.com/”);
%>

ASP .NET Redirect

<script runat=”server”>
private void Page_Load(object sender, System.EventArgs e)
{
Response.Status = “301 Moved Permanently”;
Response.AddHeader(”Location”,”http://www.new-url.com”);
}
</script>

JSP (Java) Redirect

<%
response.setStatus(301);
response.setHeader( “Location”, “http://www.new-url.com/” );
response.setHeader( “Connection”, “close” );
%>

CGI PERL Redirect

$q = new CGI;
print $q->redirect(”http://www.new-url.com/”);

Ruby on Rails Redirect

def old_action
headers["Status"] = “301 Moved Permanently”
redirect_to “http://www.new-url.com/”
end

Redirect Old domain to New domain

Create a .htaccess file with the below code, it will ensure that all your directories and pages of your old domain will get correctly redirected to your new domain.
The .htaccess file needs to be placed in the root directory of your old website (i.e the same directory where your index file is placed)

Options +FollowSymLinks
RewriteEngine on
RewriteRule (.*) http://www.newdomain.com/$1 [R=301,L]

Please REPLACE www.newdomain.com in the above code with your actual domain name.

In addition to the redirect I would suggest that you contact every backlinking site to modify their backlink to point to your new website.

Redirect to www

Create a .htaccess file with the below code, it will ensure that all requests coming in to domain.com will get redirected to www.domain.com
The .htaccess file needs to be placed in the root directory of your old website (i.e the same directory where your index file is placed)

Options +FollowSymlinks
RewriteEngine on
rewritecond %{http_host} ^domain.com [nc]
rewriterule ^(.*)$ http://www.domain.com/$1 [r=301,nc]

Please REPLACE domain.com and www.newdomain.com with your actual domain name.