To restore a missing or corrupted /etc/fstab file

1. Log in under maintenance mode.
2. Remount the root file system in read-write mode

          If /etc resides in /, then it should be read/write and you can edit fstab.

                  mount -o remount,rw /

or  mount -o rw /dev/sda1 /mnt/sda1

MySQL 5.5 and 5.1 on CentOS 5.5

MySQL 5.5 and 5.1 on CentOS 5.5

1.       Backup  old mysql permission

2.       Delete old mysql permission

3.       Untar database

4.       Update trigger using mysql front tool . 

a.       List of dbs  -- dtr_log ; dtr_log_txn; event_tb_ob_txm

See Image below

5.       Export proc.sql fr.  any of the db slave servers then import to 50.26.

6.       Execute mysql_upgrade

7.       Execute mysqlcheck –all-databases  --repair

Link to upgrade:

http://www.webtatic.com/packages/mysql55/

MySQL 5.5 and 5.1 on CentOS 5.5

In a couple of days, MySQL 5.1 will move to extended lifecycle support, where only security fixes and the most severe bugs are fixed. MySQL 5.0 has bee like this for a year already. Typically, extended lifecycle will last for two years, after which will become end-of-line, where no support is guaranteed.

CentOS 5.x has been providing MySQL 5.0 in it’s distribution since that was the active stable branch when CentOS 5.0 was released on 12th April 2007 (or more specifically it’s upstream distribution RHEL 5, which was released 14th March 2007). Since then, Sun/Oracle have released MySQL 5.1 and MySQL 5.5, so the Webtatic Yum repository has added them to it’s web stack, which now provides updated versions of all the AMP in LAMP.
This release is different from the previous packages, since it is important to only upgrade MySQL when you are ready, and you may want to chose to follow only 5.1 updates or 5.5 updates. This does mean though that you will have to uninstall your current mysql installation first.

First, to set up the yum repository, install the webtatic-release RPM:

rpm -Uvh http://repo.webtatic.com/yum/centos/5/latest.rpm

MySQL client library is used with several CentOS packages, so to remove MySQL without them, I have a mysql client library which is independent of the client tools, which can be installed first to be used instead.

yum install libmysqlclient15 --enablerepo=webtatic

Then you can uninstall MySQL:

yum remove mysql mysql-*

Then install the new MySQL version (either mysql51 or mysql55 can be installed here):

yum install mysql55 mysql55-server --enablerepo=webtatic

You should upgrade existing tables before setting the server to become a production machine, which can be done by starting the server and running the mysql_upgrade script (this may take time depending on the size of the database).

service mysqld start

mysql_upgrade

PXE server with clonezilla

Server IP: xxxx.xxx.xxx.xxx located on Proxmox 103

How to use:

1.        On the client PC, Enable Boot rom on Bios and select it as the first boot priority.

2.       Since the server is on the .60/.70 network, connect the lan cable of your client pc on the said network.

3.       Select your OS of your choice.

Install Fedora 8

1.        On the PXE server menu, choose “Install or upgrade a Fedora 8 Operating System”

2.       Select English as the Language.

3.       Select US as the type of Keyboard

4.       On the “Installation method” select “HTTP”.

5.       Choose DHCP on the TCP/IP

6.       Input “192.168.70.234” on the Web site name.

7.       Input “f8_i386” on the “Fedora Directory”.

8.       Continue on the installation.

Install Centos 6

1.        On the PXE server menu, choose “Install or upgrade a Centos 6 x86_64 Operating System”

2.       Select English as the Language.

3.       Select US as the type of Keyboard

4.       On the “Installation method” select “URL”.

5.       Choose DHCP on the TCP/IP

6.       Input “192.168.70.234” on the Web site name.

7.       Input “centos6_x86_64” on the “Fedora Directory”.

8.       Continue on the installation.

How to use clonezilla.

A.       Set your PC as an image:

1.        On the PXE server menu, choose “Clonezilla Live “Ramdisk”)

2.       Choose “English” as language.

3.       The select “Don’t touch Keymap”

4.       Select “Start _Clonezilla Start CloneZilla”

5.       The choose “device-image work with disks or partitions using images”

6.       For easy use, select the “Use ssh server”

7.       Then input the server’s IP address (192.168.70.234)

8.       Select the default ssh port “22”.

9.       Select the default user “root”.

10.   The select the default Clonezilla image directory “/home/partimag”.

11.   Enter the server password (callbox).

12.   Select Beginner Beginner mode: Accept the default options.

13.   On the Clonezilla select mode, choose “savedisk  save local disk as an image

14.   Then input your selected filename for the image.

15.   Select the desired drive to clone.

16.   Just skip all the checking /repairing source file system.

B.       Restore an image to your client PC:

1.        On the PXE server menu, choose “Clonezilla Live “Ramdisk”)

2.        Choose “English” as language.

3.       The select “Don’t touch Keymap”

4.       Select “Start _Clonezilla Start CloneZilla”

5.       The choose “device-image work with disks or partitions using images”

6.       For easy use, select the “Use ssh server”

7.       Then input the server’s IP address (192.168.70.234)

8.       Select the default ssh port “22”.

9.       Select the default user “root”.

10.   The select the default Clonezilla image directory “/home/partimag”.

11.   Enter the server password (callbox).

12.   Select Beginner Beginner mode: Accept the default options.

13.   Choose “Restoredisk  Restore an image to local disk”

14.   Then select the image file on the saved image list.

15.   Select the desired drive to clone.

16.   Just skip all the checking /repairing source file system.