Sunday, December 29, 2013
Check These Things Before Implementing the BYOD Policy
Wednesday, November 20, 2013
Starting MYSQL in innodb recovery mode
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.
Tuesday, November 19, 2013
Convert Time stamp from UNIX to Human readable format in SQUID Proxy Log
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.
Thursday, October 31, 2013
Junk values after Converting a document to PDF in Adobe
Issue:
While converting Word Documents to Adobe PDF, sometimes we observe the below error message.
%%[ ProductName: Distiller ]%%
Cambria not found, using Courier.
%%[Page: 1]%%
%%[ Error: invalidfont; OffendingCommand: xshow; ErrorInfo: CharOffsets 82 30 44 29 59 52
0]
([1]
)
%%[ Flushing: rest of job (to end-of-file) will be ignored ]%%
%%[ Warning: PostScript error. No PDF file produced. ] %%
Resolution:
This error can be resolved by changing one of the Adobe PDF printer settings.
- When you are in the print dialog, and you have selected the appropriate PDF printer, select "Properties."
- In the dialog box, there should be a tab titled "Adobe PDF Settings," and it should look like the below image.
- Un-check "Rely on system fonts only; do not use document fonts."
- This solves the issue for documents created using XP or Vista, then upgraded to Windows 7. The Cambria font somehow gets changed between XP/Vista and Win7.
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
Wednesday, October 30, 2013
Ubuntu Installation Video Tutorial
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
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/
a2enmod ssl
cd /etc/apache2/sites-available/
a2ensite default.ssl
service apache2 restart
https://localhost/
If the default webpage is loaded then you have successfully installed and configured apache2 with SSL support.