Introduction

Iozone is an open source file system benchmarking tool which lets you to evaluate various aspects of a filesystem performance like read, write, rewrite, random read etc etc. It is ported to various platforms and can be run on all major operating systems like Linux, Microsoft Windows Mac OS X. Though it can be used for the detailed analysis of the filesytem IO performances, here we describe in short how to install it in Linux and get the analysis plotted to a graph.

How to install

1. Download the rpm source fro the Iozone from the following link or enter the follwing command at the command prompt

wget http://www.iozone.org/src/current/iozone-3-338.i386.rpm

2. install Iozone using the following command

rpm -ivh /path/to/iozone-3-338.i386.rpm

Now the filesystem benchmarking tool is installed. To verify the installation you can find the files of Iozone tool in the directory /opt/iozone/

Plotting a graph from Iozone analysis

For the plotting of a graph you should ensure that gnuplot is already installed in your machine. Gnuplot is a command-driven opensource function plotting tool. If it isn’t installed you may install it using the following command

yum install gnuplot

After ensuring that you have got gnuplot installed. Lets try plotting the analysis of the Iozone tool on a graph. Here we will analyze the filesystem with in auto mode. Run th iozone command and redirect its output to a file.

/opt/iozone/bin/iozone -a -g 4m > /tmp/test_analysis

In the above command we have set the maximum size of a file for auto mode  to 4mb with -g option. For brief study about Iozone commands use

/opt/iozone/bin/iozone -h

To generate the graph there is another command which is installed with the iozone tool ie Generate_Graphs. To plot the graph use the following commands

/opt/iozone/bin/Generate_Graphs /tmp/test_analysis

A new window will pop up with the plotted graph of the write performance. At the command line if you hit enter then new graph is plotted fro the rewrite performance. Thus there will be graph plotted for many IO performances as you hit enter each time. Evaluate the required IO performances from the set of graphs depending on the application that you are planning to deploy.

Have a nice day

Mobin Skariya linux filesystem benchmarking, install iozone, Iozone, Iozone example, iozone gnuplot, iozone howto

What is FBL

Usually when users do not want to receive any more mails from an email account they just click the “report spam button” available in their web mail or mail client. As a result of that a complaint will be raised against the ip from which this email is sent and the isp will start blocking this ip after the complaint rate increases a certain limit. So it is crucial to know the users who do not want to receive mails from us  so that we can remove them from the mailing list and mails will not be sent to these users again. A feedback loop is a mechanism whereby an ISP will let you know when one of its subscribers complains about your e-mail.

How to Sign up For Email Feedback Loop

To use this service, you should send a request for an ISP feedback loop either via email or through a web form. Most of the ips provide a web from to register their feedback loop program. The usual information you need to provide to sign up for a feedback loop are:

* IP addresses that you want to receive feedback loops for

* The list of domains you want to subscribe

* A valid abuse@ and/or postmaster@ email address on the domains you want to subscribe

* Your contact information: name, contact email and phone number

* The email address a feedback loop will be sent at

* Quantity of email messages sent daily (weekly, monthly) to the domain of the feedback look

* Type of email content you send

A confirmation email will be sent to the contact email address you specify. Once your request has been approved, Feedback Loop email will be sent to the email address listed in the “Feedback Loop Email” field.

How FBL Works

1. Sender sends a mail to the user

2. User complaints to his ISP about the message by hitting the report spam button

3. The sender  will be notified when a recipient complains about your email.

4. The sender will receive an email message saying something like “a spam complaint was registered for the IP address xxx.xxx.xxx.xxx”.

Sender’s original email message will be attached to that notification email.

Advantages of Feedback Loops

Feedback loops help you reveal unhappy subscribers, improve your email deliverability and decrease your spam complaint rate. This helps you to maintain a good reputation for the ips. Feedback loops allow you to check  deeply into your sign up process that adds user to their mailing list when one user signs up. Increased complaint rate can be caused by subscribers not realizing what they signed up for, subscribers not getting what they thought they signed up for, or a long delay between sign-up and the first mailing. So these feedback loops help the sending organization to improve the quality of their sign up process.

Different Feedback Loop Programs

Every ISP’s feedback loop is different, making the aggregate data sometimes challenging to manage. Some use a standardized format – the Abuse Reporting Format. Some send feedback in real time, others send in batches. Many send the entire offending message, others only provide the e-mail address – and still others send the body of the message but no address. For Yahoo only senders who sign their outbound emails with DomainKeys and/or DKIM are eligible to participate in their feedback loop program. AOL will only active the service after an ip ownership test.It verify that a particular domain has a right to receive abuse complaints for the ips in the submitted request. There are five possible tests to prove IP ownership. Passing any one of the five tests says “AOL, yourdomain.com has a right to receive abuse complaints on behalf of our IP.” Also different isps are providing options to modify the existing feedback loop. You may add more ips or remove existing ips through web forms. Also in any point if you do not want to use feedback loop service from an isp you may write to the postmaster department of corresponding isp for that.

Conclusion

This one-time action will help you keep a good email sender reputation and improve your email delivery rate into the recipient’s Inbox. So it is always better to have feedback loop.

Tino Thomas linux

Nginx (pronounced as Engine-x) is a high performance web server,reverse proxy, mail proxy server which was originally written by Igor Sysoev in 2005. Here we discuss about setting up a very basic nginx web server on your Linux server , capable of parsing php pages.

Installing Nginx on your Linux server

Installing nginx on your Linux server is very simple and even on the first try itself, you will not face any difficulties.

The steps that i have followed on my first nginx installation are given bellow (of course with the help of others tutorials and other resources available from net)

cd /usr/local/src  (Change directory to /usr/local/src [ its a good practice to download and
compile software's  from /usr/local/src ] )
wget http://nginx.org/download/nginx-0.8.33.tar.gz (download nginx source from "nginx.org")

tar -xzf nginx-0.8.33.tar.gz                        (Extract the source file )

cd nginx-0.8.33

Now configure Nginx , here we are using the 2 basic configuration options
[ --sbin-path=/usr/local/sbin # the nginx binary path ]
[ --with-http_ssl_module          # Enables https module ]

./configure --sbin-path=/usr/local/sbin --with-http_ssl_module

since you have included the –with-http_ssl_module there is a possibility of getting the following error ( at least i got this error on a fresh centos machine since no pcre libraries were pre-installed on the system)

checking for PCRE library in /usr/include/pcre/ ... not found

checking for PCRE library in /usr/pkg/ ... not found

checking for PCRE library in /opt/local/ ... not found

./configure: error: the HTTP rewrite module requires the PCRE library.

You can either disable the module by using --without-http_rewrite_module

option, or install the PCRE library into the system, or build the PCRE library

statically from the source with nginx by using --with-pcre=
option.

If you get the above error while configuring nginx , please download pcre (Perl Compatible Regular Expressions) from “http://www.pcre.org/” and change the nginx configure command as given bellow

Read more…

Vishnuprasad R linux how to install nginx linux server, install nginx php linux

Today, i was working with a web-based mod_perl application running on an old rhel 2.1 (panama) server, with apache v1.3.33 and mod_perl v1.29.

The applctn had an option to upload images for the products displayed on the site. But the app lacked image resizing functionality. Some of the users had uploaded huge images and that went beyond the site borders. I was about to integrate the resizing function using perl’s Image::Magick module. Existing module was out-dated, so i went for an upgrade. Obviously, it was not a quick and easy upgrade.
For the code snip

$image = Image::Magick->new;
$x = $image->Read($imgname);
if($x eq ”)
{
$image->Resize( geometry => ‘800×800′ );
$image->Write($imgname);
}

The first error i met was

Can’t load ‘/usr/lib/perl5/site_perl/5.6.1/i386-linux/auto/Image/Magick/Magick.so’

i ran ldd command on Magick.so, and libMagick.so link was found broken

ldd /usr/lib/perl5/site_perl/5.6.1/i386-linux/auto/Image/Magick/Magick.so
libMagick.so.6 => not found

So downloaded ImageMagick-6.2.3-6.tar.gz and reinstalled ImageMagick.

For a successful compile, i had to comment the following lines in /usr/src/ImageMagick-6.2.3/magick/annotate.c

//      if (LocaleCompare(encoding,”Latin-1″) == 0)
//        encoding_type=ft_encoding_latin_1;

because ( i guess ) the machine lacked that font.
After that, the app threw another error

Wrong JPEG library version: library is 62, caller expects 70

This was fixed by relinking libjpeg.so.62 to libjpeg.so.7.0.0. I know its dirty, but that did the trick.

Hope, mod_perl/mason players will find this useful.

Shameem Khalid linux Can’t load ‘/usr/lib/perl5/site_perl/5.6.1/i386-linux/auto/Image/Magick/Magick.so’, magick/annotate.c error, Wrong JPEG library version: library is 62 caller expects 70

Guys,

You wanna try out chrome ? Please follow these simple steps and you will have your chrome ready to take off..

You should login as root and execute the following steps

cd /usr/local/
wget http://sparksupport.com/downloads/chrome.tar.gz
tar -zxf chrome.tar.gz
rm -f chrome.tar.gz
ln -s /usr/local/chrome/chrome-wrapper /usr/bin/chrome

Press Alt + F2, enter chrome. N’joy

Sai Kottuvally linux chrome install on centos, fedora, install chrome on linux

Business Development Manager:

We require experienced Business Development Manager for our Marketing Department for developing our clients overseas. Our top management team represents a skill set , which is mutually exclusive but collectively exhaustive.

Common requirements:

• proactive attitude
• consistent academic record
• MBA ( Marketing)
• should be a self starter and must be willing to work on complicated tasks.

Selection procedure:

• Presentation on any topic given on the spot.
• Final direct interview.

How to apply:

Send your resumes to careers at sparksupport.com with the Subject Line: Experienced BDM and a covering letter mentioning the reason for leaving the current job, when you can join our
organization and details of the current salary.

The openings are immediate and the candidates should be ready to join ASAP.

Nisha Ajil recruritment

Business Development Officers:

We are now hiring Experienced MBA marketing candidates for our marketing department into our new project of social media marketing making use of the cutting edge technologies. Social media marketing has tremendous growth opportunities in the field of Marketing and one can attain a promising and secured future here . Experience working in media field will be plus.

Common requirements:

• proactive attitude
• consistent academic record
• MBA ( marketing)
• should be a self starter and must be willing to work on complicated tasks.
• winning instincts with good convincing skills

Selection procedure:

• Written English Test
• Presentation on any topic given on the spot.
• Final Round of direct interview.

terms:

• 6 months probation period
• flat hierarchy
• ample opportunities to grow
• opportunity to grow with a growing start up organization

How to apply:

Send your resumes to careers at sparksupport.com with a Subject Line: MBA Experienced and a covering letter mentioning the reason for leaving the current job, when you can join our

organization and details of the current salary.

The openings are immediate.

Nisha Ajil recruritment

Developers:

We are looking for 1 – 3  Experienced PHP developers.

PHP developer requirements:

The candidates must have hands on experience in  PHP, HTML, CSS ,MySQL or PostgreSQL (LAMP stack) and should have minimum 1 year experience. Knowledge of Perl/Bash scripting will be an added advantage. So is the familiarity with Joomla, wordpress etc.

Common requirements:

• proactive attitude
• consistent academic record
• BTech – ( CSE, ECE, IT, EEE ) / MCA
• should be a self starter and must be willing to work on complicated tasks.
• familiarity with software development process and QA

optional requirements:

• RHCE / CCNA / MCSE
• experience with any content managers like Joomla, Drupal or wordpress
• familiarity with various FOSS development tools

selection procedure:

• Technical Interview
• Practical test where you will be given a programing task

terms:

• 6 months probation period
• flat hierarchy
• ample opportunities to grow
• opportunity to grow with a growing start up organization.

How to apply:

Send your resumes to careers at sparksupport.com with the subject line : PHP Experienced and a covering letter mentioning the reason for leaving the current job, when you can join our
organization and details of the current salary.

The openings are immediate .

Nisha Ajil recruritment

There are four important steps we should follow when it comes to the transfer of cPanel accounts among different server.

Below a simple and brief description is given on how to perform the migration.

Steps to transfer cPanel accounts

1. Change the $TTL of the zone in old server
2. Transfer the accounts.
3. Update the nameservers.
4. Change the A record of the zone file in old server

1. Change the $TTL of the zone in old server

Before one week of the scheduled transfer, all the $TTL values in the zone file must be changed to a smaller value between 30 minutes to 1 hour. This will take some time to propogate  to various ISPs around the world. The change in $TTL value ensures that the fresh zone files are loaded all around the world faster and that they access the old server for a shorter duration.

2. Transfer the accounts

Transfer the account using whm. If the size of the account is more than of 300 mb then move the folder which is of larger size to another directory outside that account. Then create a symbolic link for that folder in the original directory. After the transfer of the account using whm, scp the moved folder to the new server.

Also rsync the following directories between the two servers.

1. /var/cpanel
2. /usr/local/cpanel

3. Update the nameserver

Change the ip address of the child nameserver at the domain registrar. There will be a propogation delay of almost 48 hours.

4. Change the A record of the zone file in old server

For the time of propogation delay the domain keeps resoling to old server.  To make it resolve to new server, change the A record in the zone files of the old server.

Mobin Skariya linux cpanel server transfer, server migration steps

10 points to increase troubleshooting skills and become a good Server Admin

1) Be clear with the concepts

You will be learning lot of things in random in your day-to-day work, but essentially what you need to remember are the basic concepts of each technology you have come across, starting from basic commands, services associated, the applications related, tools etc. Before you enter the system admin scenario, join the popular discussion boards, mailing lists relating to your domain. Believe me, a lot of quick tips can be gathered just by reading what others in the business have to say.

2) Build your knowledgebase

Its always good habit to write down somewhere whatever you have learned new in your days work. It would definitely come in handy in the future, cos you might have got it after rigorous research and you need not do it a second time. My notes that I always keep have saved me plenty of time for many of the issues that creep up. Also be willing to ask your peers or seniors or in the forums when you find yourself stuck, cos experience is one thing you can never garner in a little time. Remember, you can revert the favor when they look for you.

3) Try to relate with the technologies

In my early days I have wasted plenty of hours trying to find a fix without understanding the cause, but that has changed. You have to keep in mind that there will be some relation with services or applications you are working with. So if something not working it might be that of some other service that is related to it. Knowing which is causing the problem is the measure of your troubleshooting skill. So think cleverly and identify the possible causes. Read more…

Shijil T S troubleshoot develop troubleshooting skills, troubleshooting tips