Failed to uninstall the device. The device may be required to boot up the computer.


Error Scenario: When you try to uninstall Ethernet card from a Windows 2003 VM machine you will get an error message “Failed to uninstall the device. The device may be required to boot up the computer”.  Even in the Safe mode we get the same error message. When you do ipconfig no ip address will be displayed it shows only “Windows IP configuration”.

Root cause of the problem: This problem occurs due to when you try to remove or add an Ethernet card in that VM for any specific reason, the Ethernet card is not actually removed from the device manager and from the windows registry.

Solution:

To overcome this issue please uninstall VMware tools and reboot the server. When you login to Windows it will prompt you for the new hardware installation for drivers.

Now install the VMware Tools and try to update driver for Ethernet card in the device management when it is yellow asterisked.

 Note: This problem has occurred to me due to SEP (Symantec End point) which corrupts the network files.

In a physical server, if the same issue occurs try to register “regsvr32 netshell.dll” and check.

In Mysql replication Slave_IO_Running:No


Root cause: The error occur due to the master log file does not match in the slave when you query in mysql “show slave status\G” .

Solution:

a. Check the master log file in mysql master by

mysql> show master status;

+——————+———-+————–+——————+

| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |

+——————+———-+————–+——————+

| mysql-bin.000154 | 107 | | |

+——————+———-+————–+——————+

1 row in set (0.00 sec)

 

mysql>

b. Compare the log file in slave by running the command “show slave status\G” and try to set the same log file in slave mysql server.

c. Go to slave mysql server and run the below command.

mysql>STOP SLAVE;

mysql>CHANGE MASTER TO MASTER_LOG_POS = 0;

mysql>CHANGE MASTER TO MASTER_LOG_FILE = 'mysql-bin.000154';

mysql>START SLAVE;

 

This solves the problem…

 

Mysql Error: ERROR 2005 (HY000): Unknown MySQL server host ‘domainName:3306’ (11004)


Root cause of the problem:

When you connect the remote mysql server either through IP address or host name, you will get an error as mentioned in the subject.This is due to my.cnf bind address is not correctly entered.

Solution:

Give appropriate host IP address or Host name in the bind address in my.cnf in the remote server.

 

How To Set Up Database Replication In MySQL


1. Configure The Master

a. First we have to edit /etc/mysql/my.cnf. We have to enable networking for MySQL, and MySQL should listen on all IP addresses, therefore we comment out the line

#skip-networking
bind-address = X.X.X.X host IP instead the default IP (127.0.0.1)

b. Furthermore we have to tell MySQL for which database it should write logs (these logs are used by the slave to see what has changed on the master), which log file it should use, and we have to specify that this MySQL server is the master. We want to replicate the database test, so we put the following lines into /etc/mysql/my.cnf:
log-bin = /var/log/mysql/mysql-bin.log
binlog-do-db=test
server-id=1

c. Then restart Mysql service and login to the mysql prompt, give the following permission.

mysql>GRANT REPLICATION SLAVE ON *.* TO ‘slave_user’@’%’ IDENTIFIED BY ‘<some_password>’;

mysql>FLUSH PRIVILEGES;

 

d.To identify mysql log file in master type the below command

 

mysql> SHOW MASTER STATUS;

 

+——————+———-+————–+——————+

| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |

+——————+———-+————–+——————+

| mysql-bin.000155 | 198 | test | |

+——————+———-+————–+——————+

1 row in set (0.00 sec)

 

mysql>

 

e. Then quit.

 

 

2. Configure The Slave

 

a. create a database name test in mysql.

 

b. Go to /etc/mysql/my.cnf in the slave server and do the following changes.

Comment the line and type the host ip address instead the default.

#skip-networking
bind-address = X.X.X.X host IP instead the default IP (127.0.0.1)

Also enable or uncomment the below line (server-id)in my.cnf

server-id=2 (here we should mention 2 instead the default 1, since the master is configured as 1)
master-host=192.168.0.100 (add a new entry)

c. Save the my.cnf file and restart mysql.

d. Go to mysql prompt in slave and type the command 
   mysql>show slave status\G;

The Slave_IO_Running: YES ; Slave_SQL_Running: Yes should be in the status yes.
If the IO running No; then the log file in master doesnot match the slave. To over come this issue

mysql>STOP SLAVE;

mysql>CHANGE MASTER TOMASTER_LOG_POS = 0;

mysql>CHANGE MASTER TOMASTER_LOG_FILE = 'required bin file';

mysql>START SLAVE;

Now test the replication in mysql test DB by manipulating creating or inserting or deleting any table in the test DB.
It should work...






Microsoft Remote FX.


Microsoft Remote FX.

Microsoft comes with rich in remote desktop services in Windows 2008 R2 (SP1). This worked greatly in Hyper-V VDI (Virtual Desktop Interface) where user can able to work with 3D and OpenGL applications, which integrate directly with Graphics card available in the server.

For more info: http://blogs.technet.com/b/virtualization/archive/2010/03/18/explaining-microsoft-remotefx.aspx

orkut site not working in ubuntu


Some of you are using BSNL broad band for internet.

Environment used:

Ubuntu 12.04 Operating System.

Problem: Unable to view orkut and some social networking site.

Solution:

The problem is due to DNS address, where correct address not configured.

I have entered the primary and secondary DNS address as 208.67.222.222
208.67.220.220 (Chennai area).

This solves my problem.

What is change block tracking in Vsphere?


We can see in some of the backup software there is an option available called change block tracking and use change block tracking for improving the backup performance (backup, restore & replication).

CBT is a new feature in vSphere that can keep track of the blocks of a virtual disk that have changed since a certain point in time. This is extremely useful for backup and replication applications that can use this information to greatly improve incremental backup and replication times.

This feature can be enabled or accessed through 3rd party applications (like any backup software) as a part of the Vstorage API for data protection.

Applications can use the API to query the VMkernel to return the blocks of data that have changed on a virtual disk since the last backup operation. You can use CBT on any type of virtual disk, thick or thin and on any datastore type except for physical mode Raw Device Mappings. This includes both NFS and iSCSI datastores.

The prerequisite of CBT is that the VM must use the version min 7 or later.

The CBT feature is disabled by default; the reason for this is there is a very small bit of overhead that occurs when using it. However this overhead is a small price to pay for the great efficiencies that happen by enabling it. This feature is not global and can be enabled on only select VMs that you want to take advantage of this functionality. It can be enabled either through the vSphere client or by using the SDK.

More info: http://itknowledgeexchange.techtarget.com/virtualization-pro/what-is-changed-block-tracking-in-vsphere/