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Really Great Article on MySQL and Web Server!

admin — Tue, 05 Apr 2011 06:35:25 +0000

Check out this great article by a MySQL expert who goes into detail how MySQL and web servers work and take on the load on servers. – link

[apt-get] How to See all Installed Packages!

admin — Mon, 04 Apr 2011 00:59:20 +0000

To see all the installed packaged on your linux servers, you can do:

dpkg -l

which will list all installed packages on your web server.

How to Add DNS Caching to Your Web Server!

admin — Mon, 04 Apr 2011 00:57:08 +0000

If you have a website that uses a lot of API requests (such as dealing with Twitter), you can save a lot of server load/costs simply by installing DNS caching to your web server.

Each DNS request (every time you request from any domain name using an API) takes anywhere between 0 to 500 miliseconds. Sometimes, adding DNS caching to your web server can make your website load in 1 second versus 10 seconds.

Anyways, it’s easy to do and here’s how to do it on CentOS/Fedora linux servers: (Ubuntu should be similar, just use apt-get install of yum)

First install Bind-utils:

yum install bind-utils

Do a command:

dig yahoo.com

Do it several times and note how many miliseconds it takes to retrieve the URL. Later, after we install DNSMasq, we will try dig command again to see if your web server has started caching DNS requests.

Install DNSMasq:

yum install dnsmasq

Edit the file in /etc/dnsmasq.conf:

Then add the following lines:

listen-address=127.0.0.1

cache-size=500

Next, edit the file in /etc/dhcp6c.conf:

Then add the following line:

prepend domain-name-servers 127.0.0.1;

Next, edit the file in /etc/resolv.conf:

Add the following lines with 127.0.0.1 first:

nameserver 127.0.0.1

nameserver 208.67.220.220

nameserver 8.8.8.8

nameserver 8.8.4.4

208.67.220.220 is DNS server of Open DNS, which I highly recommend as it’s FAST.

Also 8.8.8.8 and 8.8.4.4 are DNS servers of Google, which are also FAST.

You can however, decide to use any other DNS such as your hosting company’s.

You can do a test of how fast they are by doing a ping test such as:

ping 8.8.8.8

to test Google’s DNS server response times.

Next, you can start the DNSMasq so your web server starts caching, do:

/sbin/service dnsmasq start

Also, you will want to add DNSMasq to your chkconfig list so it will start up next time your web server reboots, do:

chkconfig dnsmasq on

To check all the processes running at boot-up, do:

chkconfig –list

That’s it!

Now do a dig command on yahoo.com, you should see 0 miliseconds after the first dig command!

dig yahoo.com

How to Install DNS Cache on Your Linux Web Server!

admin — Mon, 04 Apr 2011 00:53:35 +0000

If your website does a lot of queries via domain names such as aggregating RSS feeds or even a Twitter app site that accesses Twitter API, you might benefit from installing DNS cache on your linux web server.

For most, you would benefit from installing DNS cache because it will save you a ton of time for your server to fetch IP addreses. (could be anywhere between 5 to 500ms).

I’ve actually found a great article showing you how to do this on a Linux desktop computer. It actually works fine on web servers too.

Check out WebUpd8.com for full instructions.

Some notes on CentOS users:

You can do “yum install bind-utils” to get the dig program.