After you have done your testing, please make sure you re-enable your firewall. As it is a good practice to always have it enabled. Here’s how to re-enable it:

“An internal error occured in the vSphere Client.
Details: Object reference not set to an instance of an object.

Contact VMware support if necessary.”

Looking at the hostd.log file using ‘tail’:
tail -f /var/log/vmware/hostd.log

I got the folowing error:

“Could not convert disk adapter type 4″

The problem lies within the virtual disk descriptor file (.VMDK), in this case the lsilogic adapter was typed with capitals (LSIlogic):

Changing the adapter name to “lsilogic” (lower-case) fixed the issue!

Guess fiber channel cables don’t like bending :-)

To find out the vmnic number, simple click the error, the vmnic number is shown on that page:

To resolve this you simple have to put the nics into the “Down” state using “ifconfig”:

ifconfig vmnic3 down

To make this change more permanent (surviving reboots) you have to put the command in the file /etc/rc.local (this file is called once the host has been started)
Here is an example rc.local disabling 2 nics:


#!/bin/sh
#
# This script will be executed *after* all the other init scripts.
# You can put your own initialization stuff in here if you don't
# want to do the full Sys V style init stuff.

touch /var/lock/subsys/local
ifconfig vmnic3 down
ifconfig vmnic7 down


1. Shut down the virtual machine in question.
2. Connect the virtual machine OS disk to another virtual machine, this can be a running virtual machine (please note that you do need to reboot this machine after you are done):- Click edit settings on the running virtual machine.- Click on “Add…” to add hardware to the machine.
   - Select “Hard disk”
   - Select “Use an existing virtual disk”
   - Browse to the virtual disk.
   - Click “Next” and “Finish”

   Your running virtual machine should now look like this:

   

   Click “OK” to apply the settings.

3. Now go to edit settings again, and change the size of the virtual disk.

   Click “OK” once again.

4. Now open the console of the running machine. And start a command prompt.
5. Type “diskpart”.Within diskpart, type “list disk” to display available disks, you should notice the disk with the free space:

   

   Now select that disk, using “select disk 2″ (2 being the disk number offcourse..)
   After that, select the appropriate partition, using “select part 1″ (1 being the partition number)
   

   Now extend the partition using the “extend” command.

   

   Hooray! :-)

6. Now shut down the virtual machine, and remove the added disk. After that you can power on the initial virtual machine.

The attempt to acquire a valid session ticket for <virtual machine> took longer than expected.

Image 1: VMware error message.

The solution to this problem can be found here: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1013816

Creating a shortcut can be done in the first screen (Summary) in the Commands part.

I used PowerCLI to write a script that does the following:

• Loop through all virtual machines to check if there a snapshots created for a specific virtual machine;
• sum up all of the snapshots for a machine containing snapshots;
• e-mail a report of the above.

Here is the script:

Add-PSSnapin -Name "VMware.VimAutomation.Core"

$VIServer = "yourvirtualcenterserver.test.local"
$VIUsername = "DOMAIN\username"
$VIPassword = "password"

Connect-VIServer -Server $VIServer -User $VIUsername -Password $VIPassword

$AllVirtualMachines = Get-VM

$SmtpClient = new-object system.net.mail.smtpClient
$MailMessage = New-Object system.net.mail.mailmessage 

$SmtpClient.Host = "smtpserver.test.local"
$MailMessage.from = "notification@smtpserver.test.local"
$MailMessage.To.add("address1@test.local")
$MailMessage.To.add("address2@test.local")
$MailMessage.Headers.Add("message-id", "<3BD50098E401463AA228377848493927-1>")
$MailMessage.IsBodyHtml = 1

$MailMessage.Subject = "VMware snapshot overview"
$MailMessage.Body += "<FONT FACE='Arial, Helvetica, Geneva'><h2>VMware snapshot overview:</h2><br>"

foreach ($VirtualMachine in $AllVirtualMachines)
{
	$AllSnapshots=Get-Snapshot -VM $VirtualMachine

	if ($AllSnapshots.count -gt 0)
	{
		$MailMessage.Body += "<b>" + $VirtualMachine + "</b><br>"
		foreach ($Snapshot in $AllSnapshots)
		{
			If ($Snapshot.ID -like "VirtualMachineSnapshot-*")
			{
				$MailMessage.Body += $Snapshot.Created, $Snapshot.Name, $Snapshot.Description + "<br>"
			}
		}
		$MailMessage.Body += "<br>"
	}
}
$MailMessage.Body += "</font>"
$SmtpClient.Send($MailMessage)

• First you have to fix up the physical cabling;
• next, you have to setup up the zoning;
• up next you have to present the virtual disks to the VMware hosts.

Last but not least you need to take care of pathing for your presented virtual disks. For our HP EVA SAN, vSphere defaults to the “Most Recently Used (VMware)” policy.
In the past we used to manually load balance using fixed paths. This was mainly because the round robin policy mechanism was still in an EXPERIMENTAL status.
The round robin policy offers great advantages over the default MRU policy:

• The HP EVA offers ALUA (Asymmetrical Logical Unit Access). ALUA allows a LUN to be accessed via its primary path (via the owning Storage Processor) and via an asymmetrical path (via the not-owning Storage Processor) I/O to the not-owning Storage Processor or not-optimized path  comes with a performance penalty because the I/O has to be transmitted over the internal connection between the storage processors which does not have much bandwidth;
• using ALUA in combination with Round Robin will load balance the I/O’s over the most optimized paths for that LUN;
• the load is balanced between the two optimized paths rather then the most recently used path (as with the MRU policy).

Setting the pathing policy for each individual LUN can become quite a job. Good thing there is a way to set the default pathing policy for new discovered LUN’s using “esxcli”

esxcli nmp satp setdefaultpsp -–psp VMW_PSP_RR –-satp <Storage Array Type>

To figure out the storage array type for your virtual disk, right click a LUN and select “Manage Paths” (the screenshot highlights the Storage Array Type.