XenServer 5.6 and prblem with the xapi service

If the xapi service cannot start, or experiencing some problem with the xsconsole, try this:

http://support.citrix.com/article/CTX128316

Powershell and SQL "GO" separator

When executing a SQL statement in Powershell that contains words like "GO" it generates the error:

"Incorrect syntax near 'GO' "

The explanation stands in the fact that GO is not a SQL keyword. It's a batch separator used by client tools (like SSMS) to break the entire script up into batches.

The solutions may be to break up the script into batches, with a script like this:

private static List getCommands(string testDataSql)

{

string[] splitcommands = File.ReadAllText(testDataSql).Split(new string[]{"GO\r\n"}, StringSplitOptions.RemoveEmptyEntries);

List commandList = new List(splitcommands);

return commandList;

}

(source: http://stackoverflow.com/questions/971177/using-go-within-a-transaction)

Problem with COSBI OpenSource Mark

If the workload does not work, it's usually a problem related to the fact that COSBI cannot write the .ini file.

The problem is associated to missing drivers. Install all the drivers needed, and all will work fine :)

Repair SQL Server Database marked as Suspect or Corrupted

EXEC sp_resetstatus 'real_set_2'

ALTER DATABASE real_set_2 SET EMERGENCY

DBCC CheckDB ('real_set_2')

ALTER DATABASE real_set_2 SET SINGLE_USER WITH ROLLBACK IMMEDIATE

DBCC CheckDB ('real_set_2', REPAIR_ALLOW_DATA_LOSS)

ALTER DATABASE real_set_2 SET MULTI_USER

(source: http://www.sqlservercurry.com/2011/03/repair-sql-server-database-marked-as.html)

Windows XP Activation LOOP

To solve the loop, while we are trying to activate, press Windows Key + U, then in the window that pops up press the link to the Microsoft Website, and you will have a nice browser that will fulfill your desires :)

(source: http://www.thetomorrowtimes.com/2006/12/how-to-login-to-expired-windows.html)

(Windows) NTP server for a private network

Need to have a NTP server for your private network?

You have machines that cannot access the Internet, but you need them to be time sync-ed?

I had this problem, and I solved it letting my "gateway" machine (i.e. Controller) become a NTP server.

First of all, activate the Windows Time service in Control Panel -> Administration Tools -> Services.

Then, modify the registry entry using regedit.exe in this way:

System Key: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters]
Value Name: LocalNTP
Data Type: REG_DWORD (DWORD Value)
Value Data: (0 = disabled, 1 = enabled)

(source: http://www.pctools.com/guides/registry/detail/1117/)

Unfortuately, this solution doesn't work (at least for me).

On the other hand, this other solution I found here (http://www.techrepublic.com/blog/datacenter/configure-a-standalone-ntp-server-in-windows-server/3869) works fine ^_^

System Key: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NTPServer]
Value Name: Enable
Value Data: (0 = disabled, 1 = enabled)

Putting the data value to 1 enables the current machine to become a NTP server.

Then, in a command shell update the configuration of the Windows Time service:

> w32tm /config /update

and visualize the new configuration with:

> w32tm /query /configuration

The output should appear like the one in the image

(source: http://www.techrepublic.com/blog/datacenter/configure-a-standalone-ntp-server-in-windows-server/3869)

Last step, update the new server machine using a NTP server on the Internet. If you don't do it, you can incurr in some synchronization problem on the clients, like this:

"Error (...) Peer's stratum is less than Host's stratum"

that practically means that the client doesn't trust the new NTP server, as it did not take time from anywhere.

Different thing is if you want to define your machine as a "standalone, trustable NTP server". In that case you need a Knowledge Base from Microsoft that alows to your machine to take the time only from the CMOS clock of your machine.

VirtualBox + Powershell = genius (?) in the box

Today I'm facing another strange behavior of the command-line interface "vboxmanage.exe" for Oracle's VirtualBox.

Here is the Powershell code I'm executing on a remote machine to reboot a virtual machine:

$VM = "WindowsXP";

Invoke-Command -ScriptBlock {vboxmanage controlvm $args reset} -ArgumentList $VM ComputerName 10.3.2.127

Ok, I got an error that is:

VBoxManage.exe: error: Invalid machine state: PoweredOff

+ CategoryInfo : NotSpecified: (VBoxManage.exe:...ate: PoweredOff:String) [], RemoteException

+ FullyQualifiedErrorId : NativeCommandError

VBoxManage.exe: error: Details: code VBOX_E_INVALID_VM_STATE (0x80bb0002), component Console, interface IConsole, callee IUnknown

Context: "Reset()" at line 124 of file VBoxManageControlVM.cpp

The weird thing is that on the machine that hosts the VM (10.3.2.127) the reset works fine.

I checked the execution state on both the host and the remote machine and... guess what... I discovered that the state was different: Powered Off on the remote machine, and running on the host.

host: State: running (since 2011-10-22T22:20:35.359000000)

remote: State: powered off (since 2011-10-18T14:39:32.000000000)

To be sure it was the same machine, I checked the UUID of the machine, and it is the same.

And the machine is accessible, too (it works!)

Another strange thing is the time since the VM results stopped on the remote machine, actually 4 days before, probably since the last try in "reset" the VM.

And here is the deal. When then I tried to start the machine remotely, I got this error:

Invoke-Command -ScriptBlock {vboxmanage startvm "WindowsXP" --type headless} -ArgumentList "WindowsXP" -ComputerName 10.3.2.127

Waiting for VM "WindowsXP" to power on...

VBoxManage.exe: error: Failed to open release log (could not open file 'C:\Documents and Settings\perfmon\VirtualBox VMs\WindowsXP\Logs\VBox.log' (fOpen=0x322), VERR_SHARING_VIOLATION)

+ CategoryInfo : NotSpecified: (VBoxManage.exe:...RING_VIOLATION):String) [], RemoteException

+ FullyQualifiedErrorId : NativeCommandError

VBoxManage.exe: error: Details: code E_FAIL (0x80004005), component Console, interface IConsole, callee

Then I recalled that the last time I started the VM directly from the host, and not from the remote machine.

Like this, the handler of the log file is still associated to the process which started the machine (on the host), and the powershell process, which tries to access the machine, cannot get the handler. This results in a false information about the state of the machine.

Thus, to solve the problem, I powered off the VM on the host, and I started it successfully on the remote machine:

Invoke-Command -ScriptBlock {vboxmanage startvm "WindowsXP" --type headless} -ArgumentList "WindowsXP" -ComputerName 10.3.2.127

Waiting for VM "WindowsXP" to power on...

VM "WindowsXP" has been successfully started.

and then I checked if the reset was working:

Invoke-Command -ScriptBlock {vboxmanage controlvm $args reset} -ArgumentList "WindowsXP" -ComputerName 10.3.2.127

and the machine state was:

State: running (since 2011-10-28T12:54:58.718000000)

Here we go!!! :)

Ivano 1, VirtualBox 0