Starting MYSQL in innodb recovery mode

Recently my SQL server has crashed and was unable to start, I have tried to fix the issue but could not, by seeing the log file I could only understand that there is a problem with the innodb database and the only way to work around with the issue is to recover innodb. But I cannot loose the database since it was very critical for my project.

So after little R&D I was able to start the server using the innodb recovery mode, here is how to do it

Open the mysql config file i.e. my.ini and add the following line under the [mysqld] line

innodb_force_recovery = 4

this will start the mysql server in innodb recovery mode and gives you the chance to repair the database.

For your information the mysql logfile

131121  1:18:48  InnoDB: Page checksum 4132264320, prior-to-4.0.14-form checksum 47764882
InnoDB: stored checksum 4132264320, prior-to-4.0.14-form stored checksum 1792345140
InnoDB: Page lsn 0 58314446, low 4 bytes of lsn at page end 58279508
InnoDB: Page number (if stored to page already) 590,
InnoDB: space id (if created with >= MySQL-4.1.1 and stored already) 0
InnoDB: Page may be an update undo log page
InnoDB: Database page corruption on disk or a failed
InnoDB: file read of page 590.
InnoDB: You may have to recover from a backup.
InnoDB: It is also possible that your operating
InnoDB: system has corrupted its own file cache
InnoDB: and rebooting your computer removes the
InnoDB: error.
InnoDB: If the corrupt page is an index page
InnoDB: you can also try to fix the corruption
InnoDB: by dumping, dropping, and reimporting
InnoDB: the corrupt table. You can use CHECK
InnoDB: TABLE to scan your table for corruption.
InnoDB: See also http://dev.mysql.com/doc/refman/5.5/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.
InnoDB: Ending processing because of a corrupt database page.
131121  1:18:48  InnoDB: Assertion failure in thread 2996 in file buf0buf.c line 3602
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.com.
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: http://dev.mysql.com/doc/refman/5.5/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.

Convert Time stamp from UNIX to Human readable format in SQUID Proxy Log

I work with an IT organization and my Security team as a part of their routine audits asked me to provide the SQUID proxy server log. I have provided them the logs but they were not happy about it since the time stamp in the log is in UNIX format. So they have assigned me the task to change the time stamp to human readable format.

I have started to do the R&D on how this can be achieved, after I googling for a long time I have found the solutions for it which I am explaining now since I have found many administrators searching for this configuration on the internet.

The configuration is pretty simple, we just need to add the following configuration line at the end of squid configuration file located at /etc/squid/squid.conf

The configuration is

### Custom Log Format ###
logformat squid %tl.%03tu %6tr %>a %Ss/%03Hs %<st %rm %ru %un %Sh/%<A %mt

after adding the above configuration, restart the SQUID proxy server for the changes to take effect.

That's it now the time stamp in SQUID log would be in Human Readable Format.

Install and Configure postfix

Postfix is the Linux Mail Transfer Agent that is being used very widely in recent days because of the features that it offers. Installation of Postfix is pretty simple in Debian based OS and a bit tricky in Redhat based. The following tutorial will show you the installation of Postfix in Ubunt and Redhat(in the next tutorial).

Before proceeding we need to make sure that the default MTA sendmail(if installed) should be removed. This can be done by executing the following commands

Debian or Ubuntu :

apt-get purge sendmail

Redhat :

yum remove sendmail

Now we can proceed with the installation of Postfix MTA by executing the following command as a root or a sudo user.

apt-get install postfix
apt-get install mailutils

Normally in Debian based or in Ubuntu operating systems once after the installation a wizard is started to complete the configuration of the Postfix, follow the below steps to complete the general postfix configuration

once the configuration is Done, restart the postfix service for the changes to take effect.

service   postfix   restart

Ubuntu Installation Video Tutorial

Ubuntu is the most famous Linux distribution widely used at home and at enterprises. The desktop version of Ubuntu is very stylish with amazing visual effects and very user friendly. Ubuntu comes with the software center with thousands of applications ready to install with just a click.

Installation of Ubuntu is pretty simple, here is a video tutorial that shows step by step instructions of Ubuntu 12.04 installation on a VMWARE workstation.

Enable Apache SSL in Ubuntu

Enable Apache SSL in Ubuntu

SSL (Secure Sockets Layer) is the standard security technology for establishing an encrypted link between a web server and a browser. This link ensures that all data passed between the web server and browsers remain private and integral. SSL is an industry standard and is used by millions of websites in the protection of their online transactions with their customers.

The following tutorial will tell you how to configure apache with SSL and browse your website using https protocol. In ubuntu its pretty easy and the steps are as follows.

In ubuntu open a terminal and login as root and run the following commands

1. install apche2 webserver

apt-get install apache2

2. Browse to the following directory using

cd  /etc/apache2/mods-available/

3. Enable the SSL module for apache using

a2enmod ssl

4. Now browse through the following directory

cd /etc/apache2/sites-available/

5. And enable the defaulf virtual host with SSL using

a2ensite default.ssl

6. Now restart the webservice for the changes to take effect

service apache2 restart

To confirm if all went well just open the firefox browser and type the following URL in the address bar.

https://localhost/

If the default webpage is loaded then you have successfully installed and configured apache2 with SSL support.