Saturday, April 10, 2010

Site speed now affects your Google search ranking

Site speed now affects your Google search ranking: "


Bad news for internet slowpokes. Google said it will now factor in how fast a web site loads into its search rankings.

Google said that fewer than 1 percent of search queries will be affected by the change, and it only applies for visitors searching in English. The search engine considers more than 200 different variables in its rankings and changes its algorithms constantly; it said it launched this change a few weeks ago after “rigorous testing.”

Google Fellow Amit Singhal and principal engineer Matt Cutts wrote today:

Speeding up websites is important — not just to site owners, but to all Internet users. Faster sites create happy users and we’ve seen in our internal studies that when a site responds slowly, visitors spend less time there. But faster sites don’t just improve user experience; recent data shows that improving site speed also reduces operating costs. Like us, our users place a lot of value in speed — that’s why we’ve decided to take site speed into account in our search rankings.

Cutts had hinted about such a change as early as last year. The search engine has long prized speed. Experiments last year showed that slowing down the search results page by 100 to 400 milliseconds meant 0.2 to 0.6 percent fewer searches. The longer Google users were exposed to the experiment the more they decreased their searches.

Monday, June 1, 2009

RHEL/CentOS NFS installation

To install Linux over NFS, you need to have NFS server setup. Follow the below steps carefully.

  • first locate and edit /etc/exports with the preferred NFS path.
  • vim /etc/exports -> put the path. Let say, /var/ftp/pub/CentOS-5.2

NOTE :- For file editing you can use your favorite file editor. In this case I’m using “vim”, which I’m very much comfortable with. In your case it might be some thing else. Can be either nano , emacs OR gedit. If you newbie, then I’m recommending gedit for you.

vi/vim, is a very powerful text editor available under Linux, which is my personal favourite. If you are new to vim and want to try out, type “vimtutor” in your shell.

Back on NFS again…..

  • exportfs -ua -> will umount all exported file systems
  • exportfs -ra -> will remount all exported file systems
  • showmount -e hostname -> will list all exported file systems in hostname

If iptables ON, nfs probably won’t work. Most probably your nfs ports must be blocked by firewall. First clarify whether the firewall is turned on OR off in you machine.

  • service iptables status – will give the iptables status

If iptables turned on, then get a list of applied iptables rules. To do so,

  • iptables -L | less – will list current iptables rules.

If you see four strings in the below format, probably nfs might work over the firewall for you.

iptables -A INPUT -s 192.x.x.x/24 -p tcp –dport 111 -j ACCEPT
iptables -A INPUT -s 192.x.x.x/24 -p udp –dport 111 -j ACCEPT
iptables -A INPUT -s 192.x.x.x/24 -p tcp –dport 2049 -j ACCEPT
iptables -A INPUT -s 192.x.x.x/24 -p udp –dport 2049 -j ACCEPT
NOTE :- IP addresses used here are belong to IPV4 private ranges. Replace it with yours.

If not we need to allow nfs over iptables. To allow NFS over iptables :-

  • iptables -A INPUT -j ACCEPT

NOTE :- More general rule that will allow all incoming traffic through the firewall. Later I’ll discuss NFS over firewall in much detail in a up-coming post.

  • service iptables save; restorecon -R /etc/sysconfig/* – will save iptables settings and restore selinux context.
  • service iptables restart.

nfs should be OK over iptables by now. Let’s get start the installation.

Start system with the help of the boot CD/DVD. In the boot: prompt, Either you can press enter and go ahead with booting the system, which later prompt for the installation method OR Press F2 and go to options and invoke “linux askmethod”. In each you’ll be asked to select language , keyboard , and installation method. Select “NFS” for installation method.

To Configure TCP/IP, you can use either static IP or DHCP. If you have DCHP server in place use DHCP or use a correct static IP.

NOTE :- you will find DHCP settings in a up coming post.

In NFS setup ->

under the nfs server name : use name OR IP of the NFS server
under the CentOS/RHEL directory : /use/correct/path/

If everything went right system should start the installation.