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Change UUID of Vdi in Virtualbox

Making  copy of the .vdi file into another location will make a real copy of the virtual disk, including the UUID of the disk. If this disk is added to  the Virtual Media Manager, you  will get an error like this:


To chage the UUID of disk use following command

$ VBoxManage internalcommands setvdiuuid /path/to/virtualdisk.vdi
VirtualBox Command Line Management Interface Version 2.2.2
(C) 2005-2009 Sun Microsystems, Inc.
All rights reserved.

UUID changed to: 9e89fe14-d010-469e-a737-cd6521889acb

Since the old UUID is change , you can now add this virtual disk to Disk Manager

You need not use this commmad if you use clonevdi function to duplicate the virtual disk image, in the first place. The clonevdi  makes the new disk image with unique UUID.

The syntax of the clonedvi goes like this:

$ VBoxManage clonevdi_Master.vdi Clone.vdi


Remove SQL Server Password

Reset Forgotten Sa password

To configure startup options

  1. Login computer from administrator Account
  2. At  SQL Server Configuration Manager, click SQL Server Services.
  3. In the right side, right-click SQL Server (<instance_name>), and then click Properties.
  4. Startup Parameters boxtype the parameters separated by semicolons (;). at the Advanced tab, ,

    For example, to start in single-user mode, insert -m; in front of the existing startup options, and then restart the database.

    you must remove the -m; after  finished using single-user mode, from the Startup Parameters box before you can start a multiuser mode in production.
  5. Click OK.
  6. Restart the Database Engine.
  7. Change security authentication mode (You may not require this step if you have already enabled sa user)
    1. In SQL Server Management Studio Object Explorer, right-click the server, and  click Properties.
    2. On the Security page, under Server authentication, select the new server authentication mode, and click OK.
    3. In the SQL Server Management Studio dialog box, click OK to acknowledge the requirement to restart SQL Server.
    4. You can change password here.
  8. Enable the sa login by using Management Studio(You may not require this step if you have already enabled dual authentication )
    1. In Object Explorer, expand Security, expand Logins, right-click sa, and then click Properties.
    2. On the General page, you might have to create and confirm a password for the sa login.
    3. On the Status page, in the Login section, click Enabled, and then click OK.
  9. Now you can logon with sa user and password .You can also set permission of the local user account from that.


install bandwidthd ubuntu

Installing bandwidthd for Network Monitoring in Ubuntu Server

1. Install bandwidthd :   #apt-get install bandwidthd
2. follow prompts, main config file is /etc/bandwidthd/bandwidthd.conf.  You can  copy the conf file from /usr/share/doc/bandwidthd/bandwidthd.conf to /etc/bandwidthd/bandwidthd.conf
3. Install apache2    #apt-get install apache2
4. Change directory  to /var/www and create a soft link to the htdocs directory that bandwidthd uses (check /etc/bandwidthd/bandwidthd.conf for default bandwidthd path ).The softlink of bandwidthd is  created using this command
# ln -s /var/lib/bandwidthd/htdocs bandwidthd

5. restart apache /etc/init.d/apache2 restart (and bandwidthd if needed /etc/init.d/bandwidthd restart)
6. To access bandwidthd
http://<IP of the PC>

Mysql slow query from IP other than localhost

From long time I have faced Mysql slow query from IP other than localhost it was retrieved from another PC but localhost was working well.After much toiling for the answer I found that placing “skip-name-resolve” as a line in my.cnf solved the issue. ,This worked  even though no user rights in my database not assigned any names, only IP addresses.

When a client connects to mysqld, mysqld spawns a new thread to handle the request.This thread first checks whether the host name is in the host name cache.
If not, the thread attempts to resolve the host name The thread takes the IP address and resolves it to a host name. It then takes that host name and resolves it back to the IP address and compares to make sure it is the original IP address so this thread significantly increases the query time and slows down the system.This reverse DNS is suitable for the system connected to internet for letting certain domains to except the request but for system in the local LAN has to suffer a lot time since the local IP normally does not resolve to a name.