What is load test and why is it necessary?

Load test is the process of putting load on system and testing its response, its a way to determine how your system reacts under heavy load. You need load test for a website to determine possible issues which you may face under heavy traffic environment. For example http response may fail in case of heavy traffic or response time will increase tremendously.

What is ab and how to get it?

AB stands for apache benchmark. You can install it under ubuntu using following command

sudo apt-get install apache2-utils

How to use AB?

Open terminal and input following command.

ab -n 100 -c 5 http://example.org/

Note: Dont forget to append trailing slash, else it won’t work.

It follows the following format:

ab -n [number of connections] -c [number of concurrent users] [webpage to load test]

It will generate following output:

This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking example.org (be patient).....done
Server Software: Apache
Server Hostname: example.org
Server Port: 80

Document Path: /
Document Length: 85424 bytes

Concurrency Level: 3
Time taken for tests: 86.730 seconds
Complete requests: 100
Failed requests: 12
(Connect: 0, Receive: 0, Length: 12, Exceptions: 0)
Write errors: 0
Total transferred: 8571728 bytes
HTML transferred: 8516828 bytes
Requests per second: 1.15 [#/sec] (mean)
Time per request: 2601.912 [ms] (mean)
Time per request: 867.304 [ms] (mean, across all concurrent requests)
Transfer rate: 96.52 [Kbytes/sec] received

Connection Times (ms)
           min     mean         [+/-sd]    median    max
Connect:   323     342          52.8       326       687
Processing:1847    2256         700.6      2086      6737
Waiting:   388     411          65.4       393       814
Total:     2171    2598         729.3      2415      7187

Percentage of the requests served within a certain time (ms)
50% 2415
66% 2421
75% 2471
80% 2504
90% 3207
95% 3769
98% 6528
99% 7187
100% 7187 (longest request)

Understanding output

Server Software: Apache
Server Hostname: example.org
Server Port: 80

First three lines says server which is being tested is apache server whose hostname is example.org

Document Path: /
Document Length: 85424 bytes

Next two lines says, the page being tested is / (it will be /index.php if you will put url as http://example.org/index.php)  and length of one page is 85424 bytes.

Concurrency Level: 3

AB is sending 3 concurrent request at a time. You should set it according to requirement. Its very rare that people will hit same page exactly same time. This only happens when your site is facing very heavy traffic all the time. Your website/webserver may behave very differently in case of too many concurrent connection for example race condition.

Time taken for tests: 86.730 seconds

This is total time taken by AB.

Complete requests: 100

Number of request sent by AB.

Failed requests: 12
(Connect: 0, Receive: 0, Length: 12, Exceptions: 0)

Number of request failed. As I mentioned earlier in case of heavy traffic or high concurrency a request may fail. This is the number of request failed. If it is too much you should start worrying.

Write errors: 0
Total transferred: 8571728 bytes

This is total data (HTML and Header) transferred by AB during test.

HTML transferred: 8516828 bytes

This is total HTML data transferred by AB during test.

Requests per second: 1.15 [#/sec] (mean)

This is a measur of your server’s capacity. It says your server can withstand 1.15 request per second when it is facing this much of load.

Time per request: 2601.912 [ms] (mean)
Time per request: 867.304 [ms] (mean, across all concurrent requests)

This is average of total time taken since a request is sent and a response is totally downloaded.

Transfer rate: 96.52 [Kbytes/sec] received
Connection Times (ms)
           min     mean         [+/-sd]    median    max
Connect:   323     342          52.8       326       687
Processing:1847    2256         700.6      2086      6737
Waiting:   388     411          65.4       393       814
Total:     2171    2598         729.3      2415      7187

Above lines means minimum time taken for a request to complete is 2171 ms, maximum time is 7187 sec, while average time is 2598 ms with standard deviation of 729 ms.

Percentage of the requests served within a certain time (ms)
50% 2415
66% 2421
75% 2471
80% 2504
90% 3207
95% 3769
98% 6528
99% 7187
100% 7187 (longest request)

Above lines shows that more than 80% of the requests were served within 3 secs, but when number of open connections increased time taken to serve each request increased more than two times.

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Have you been embedding CSS Styles into PHP files just for the sake of making the styles dynamic?
Ever wished to add PHP codes in CSS files itself.

Here is a simple trick which will do the magic.

Create a .htaccess file in your project directory preferably inside the directory where CSS files are stored. Open .htaccess file and add following line

Now you can include php codes in CSS files. Here is a small example

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So u have given a SVN Checkout command or apt-get install command which will take unexpected time to end.

Here is a way to get notified when process ends. Just append notify-send “Complete”; to the command

For example
You want to execute

sudo apt-get install -big-software-

and want to get notified after installation.Then use following command

sudo apt-get install -big-software-; notify-send “installation complete”;

and you will be notified using ubuntu’s notification-daemon once the installation completes.

Cheers

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Last night my computer’s hard disk crashed. Thankfully it was under guarantee period so I gave it for repairing. Computer’s hardware was lying worthless in my desk, and I got a rare chance of experimenting. So I decided to install linux in a pen drive, although I could do that even if HDD was present, but who has time for that ? huh !

I had a bunch of linux distros with me, thanks to to linux for you magazine. I took out ubuntu’s DVD (10.04) which is my favorite Linux flavor and started installing it in my 4Gb pendrive. Unfortunately I could not succeed due to unknown reason.
I tried Mandriva Spring 2010 next, but its partition manager (I suppose GParted) crashed prior to installation. My bad luck.

Although I had no expectation from Fedora (this is personal, don’t draw any conclusion), It worked. Installation process was exactly same as installing on a hard disk, the only difference was the freaking slow progress rate, reason being slow transfer rate of pen-drive.  At least it was done successfully, that was all I needed to be “happy”.

For the first time in my life I logged into a fedora system. It looked similar to ubuntu (this is what happens when you keep using one destro, being afraid of the time you would waste making yourself comfortable with other). Then I realized, if looks are the only thing you care about in Linux then choose between Gnome and KDE not among deferent linux flavors. So I started diving deep into finding at least one difference that matters a lot and that does not include ubuntu has ubuntu software center and fedora does not.

Well the search is ON, I might find something when I use my computer again, hopefully before repaired hard disk arrives. Till then I am using my Laptop and babuji is using that freaking slow PC. He he he

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Ever faced the problem that kaspersky’s blacklist licenses is corrupt and even updating antivirus does not solve the problem.
It generally happens due to power failure which sometimes corrupt license data.

Here is a quick solution

First disable “Self defense” capability of kaspersky from settings.
Then pause kaspersky and delete blacklist files.
You can find the files in
C:\Documents and Settings\All Users\Application Data\Kaspersky Lab\AVP[version]\Bases\bl00*.dat
If you are an XP user and

C:\ProgramData\Kaspersky Lab\AVP[version]\Bases\bl00*.dat
If you are using Vista/win7

Note: Replace [version] with your kaspersky version. Its 11 in my PC.
Note: bl00*.dat means very file with name bloo[something-something].dat

You can then resume kaspersky and enable self defense.
Now update kaspersky and it will download the blacklist files again.

Thats it. Problem Solved.

Cheers

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Here is a small trick to hack your friend’s password.
You wont be able to know old password but you surely will be able to change it.

Step 1: Just start Command Prompt as an administrator.
Goto Start >> All programs >> Accessories >> Command Prompt (Right Click) >> Run as administrator

Step 2: You will be presented with a black screen.  Type
Net user
You will get a list of users.

Step 3: Now write
Net user <username> <new password>
(without < and > ofcourse)

Voila ! Password changed. Now u can ask him ransom to tell his new password.

Troubleshooting
1. I got an Error 5, access is denied.
>> This happens when you are not running command prompt as an administrator.

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Ever clicked on Start new session by mistake?

Don’t panic, you can still get your session back. Goto navigation bar and type about:sessionrestore and wow you are presented with last session restore screen.

Cheers.

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Hello,

I saw an article on recovering lost ubuntu after installing windows. I was pretty confident and installed windows 7 on my box. After that I started following the article and I was stuck with a blank grub menu during startup.

I booted from ubuntu live DVD and started reading more about restoring grub. Here is a solution I came up with.

Its a step by step guide to restoring ubuntu.
(Note: Its for Grub2. I am using Ubuntu 10.04)

Step1: Boot using Ubuntu Live CD/DVD.

Step2: Open terminal. (Press Alt+F2 and write gnome-terminal)

Step3: Now you need to mount your root partition. You can see a list of partition by typing
sudo fdisk -l

Step4: Now mount the root partition
sudo mount /dev/sdXY /mnt
Example: sudo mount /dev/sda6 /mnt
Where sda6 is the partition where I had my ubuntu’s “/” installed.

Step5: If you had a separate boot partition. Then mount it in /mnt/boot
sudo mount /dev/sdXZ /mnt/boot
Ex: sudo mount /dev/sda8 /mnt/boot

Step6: Now install grub
sudo grub-install –root-directory=/mnt/ /dev/sdX
Ex: sudo grub-install –root-directory=/mnt/ /dev/sda
where sdX is your first hard disk from where your system boots Or where MBR is located.

Step7: Restart your computer.It will automatically boot into your old ubuntu.

Step8: Open terminal and execute
sudo update-grub

Step9: Restart your system.

DONE. Cheers

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Here is a letter I wrote to my brother telling him how to do search engine optimization for his website for fast result. I thought I must share it to world so people can  learn and suggest some ammendment(s).

_________________________________________________

Hello brother,

Here is the tutorial on Site Engine Optimization as you requested.

Before website is complete

0. Domain name
Your domain name must contain the most relevant keyword related to your site.
1. Keywords
Identify the keywords related to your site which users will search for.
Let the keywords be A, B, C, X, Y ,Z (in decreasing order of priority)
2. Meta Tag
Add these keywords to meta tag of your site. (Remove unwanted keywords)

3. Javascript
Keep HTML clean. No javascript onmouseover or onclick in HTML. Keep a separate .js file for javascript.
4. CSS
Similarly no CSS styles in HTML attach a Style sheet instead.
5. Content:
Let the content of ur site be “Hello brother X how are you B doing. We are very happy Z, Why dont you come here A for dinner ”
Chnage it to “Hello brother <h2>X</h2> how are you <h1>B</h1> doing. We are very happy <h3>Z</h3>, Why dont you come here <h1>A</h1> for dinner ”
Surround keywords with high priority with <h1> and lowest priority with <h3>
Now in style sheet redefine h1, h2, h3 tags to look normal.
h1, h2, h3 {
size = “medium”;
}
6. Page names.
Don’t name pages as “contact.htm” try to rename it to “contact_A.htm” where A is a high priority key word.
7. Title.
Every page title must contain one of the Keyword.

After website is complete

8. Socialize
Your site must have a facebook fan page.
http://www.mindmeister.com/2529908/social-media-web-sites
Check this link
There is a list of top social networking site in there. Make a fan page in each of the.
If you can maintain all of them then its good. Else at least maintain 5 of them.
Assign each site to a junior for updating information of you site at these social sites.
9. Bookmark
This is a must. The above link I gave you contains a list of bookmarking sites. Tell as many people to register at all of them as you can.
You must have more than 10 ppl having accounts in all these bookmarking site. The more you can manage the better the result will be.
Add each page of your site as a bookmark to all of them.  (This must be done by all the people)
10. News and Blogs
Subscribe to google alert about all your keywords. It will send you mail if google finds any site having your keyword.
Check each site and if there is any option of commenting on them just comment it and don’t forget to enter your website.
Comment must be meaningful and relevant else it will be rejected by the owner. Don’t advertise your website until you find its relevant.
You must add comment on news sites.
11. Questions and Answers
People will be asking questions related to event in sites like Yahoo answers. You can finds the list in the link I gave you. Dont forget to answer each for them.
12. Don’t do it alone
Whatever I wrote above won’t work if only 1-2 ppl do it. You must get a mass for doing the above things. At least 10 ppl are required.

When People start visiting

13. Don’t forget to provide the best service. Your site must have a RSS feed, a twitter account. Keep the feed and tweet flooded with important information ONLY. Site’s usability is very important. You don’t want visitors to go away after they visit your site.
So take a survey of general people implement what mass says. This must be done after your site is complete. People like watching changes.

14. Once people start talking, stop publicizing, and pay more attention to content and usability.
Even if you make it to 1st rank in google. People can find same stuff in 2nd rank website too, at that time its only your site’s design and usability that will attract them.

Usability: By usability I mean ease of finding data that they want.

___________________________________________

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In this tutorial you will learn about using Javascript DOM to Disable the page content by covering it with a layer (of div tag) or simply Graying out the screen.

A little Blah Blah

You might have seen on many websites, when you click a link, the whole page darkens and you are focused on a specific box. Here is the tutorial on how to create it.
Example www.pixel2life.com (click on login button)

Lets begin

Here is a code of the page which we are going to modify.
Old HTML code comes here

Add a div tag inside body tag. Assign it with an id say “cover”. Add following style to the cover div. Also add a div for box that will be visible when you cover(darken) the screen, let its id be “box”.

Updated HTML

CSS:

Cover

This is the div layer that will cover up the screen. So its width must be 100% of the document.
This div is just after body tag so making its position absolute we make sure that it wont cover any space after body tag (ie it will be floating).
Its position will be 0px from left 0px from right. Its opacity will be 75%.
Now we don’t want it to be active at first so we set its visibility to hidden. We added a z-index of 998 just to make sure it is placed at top.

Box

We define the height and width of box as 300px and 600px respectively. We define its position from top. Its position from left must be set by javascript to keep it in center.

All the modification to HTML and CSS are complete. Now we have to add some javascript.
Here is the code.

Now you want the cover to hide when you click on it. To make it happen just add this javascript function.

If you want to add a link in box to close the box just add the following code to the link.

USES ?

You can use it for disabling the access to page.
You can use it to focus at specific content.
You can use it to make your site look modern.

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