hi all....

I am new to linux...I have a mysql server 5.0 version on my system ....I installed a new mysql server 5.1.31 but the problem is that if i do any changes in the database by starting new mysql server...Its is getting reflecting when i start the old server and see the database....i have to change the data directory path from /var/lib/mysql to somwhere..where i need to change this...

can any one help me please...

thanks in advance...

Assuming that you are not going to run both servers simultaneously, that you can edit the start script of the 2nd mysqld, and use a different "--datadir=..." option. Of course that directory must exist and be ownned by the mysql user.
If you want both servers to run together you can follow these instructions.

i tried but iam getting error..

[root@localhost scripts]# mysql_install_db --datadir=/usr/local/mysql/data/mysql/
Installing MySQL system tables...
ERROR: 1 Can't create/write to file '/usr/local/mysql/data/mysql/mysql/db.MYI' (Errcode: 13)
090423 10:57:38 [ERROR] Aborting

090423 10:57:38 [Note] /usr/libexec/mysqld: Shutdown complete

Installation of system tables failed!

Examine the logs in /usr/local/mysql/data/mysql/ for more information.
You can try to start the mysqld daemon with:
/usr/libexec/mysqld --skip-grant &
and use the command line tool
/usr/bin/mysql to connect to the mysql
database and look at the grant tables:

shell> /usr/bin/mysql -u root mysql
mysql> show tables

Try 'mysqld --help' if you have problems with paths. Using --log
gives you a log in /usr/local/mysql/data/mysql/ that may be helpful.

The latest information about MySQL is available on the web at
http://www.mysql.com
Please consult the MySQL manual section: 'Problems running mysql_install_db',
and the manual section that describes problems on your OS.
Another information source is the MySQL email archive.
Please check all of the above before mailing us!
And if you do mail us, you MUST use the /usr/bin/mysqlbug script!

From your commands, I guess (since you didn't say) that you are trying to use the binary mysql from www.mysql.com. If that's correct, make sure that no mysqld is running and use this:
Since you're running it as root, you must after that chown the datadir to the user/group that mysqld will run (usually mysql/mysql)
After that try to start the new server using

Thank you sir..
server is starting but if i try to type mysql -u root -p
and enter it is giving the error

Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock'

This is because you're not using the full path to the new mysql installation. Using just "mysql -u root -p" will run the old mysql binary that is in your PATH, thus it will try to connect to the old mysqld server.
You have to run
Not also that you have to define a different my.cnf file for the new mysql installation, so you don't use the default /etc/my.cnf. To do this you have to add the "--defaults-file=/path/to/new-my.cnf" in both mysqld and mysql options.

Thanks a lot its working...