Archive for October, 2012

VMware Hypervisors

Posted: October 12, 2012 in ESX, VM, VMWare
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In IT, a Hypervisor, also called virtual machine manager (VMM), is one of many hardware virtualization techniques allowing multiple operating systems, termed guests, to run concurrently on a host computer. It is so named because it is conceptually one level higher than a supervisory program. The Hypervisor presents to the guest operating systems a virtual operating platform and manages the execution of the guest operating systems. Multiple instances of a variety of operating systems may share the virtualized hardware resources. Hypervisors are very commonly installed on server hardware, with the function of running guest operating systems, that themselves act as servers.

The Core of the vSphere product suite is the Hypervisor.

Hypervisor is the virtualization layer that serves as the foundation for the rest of the product line of VMware.

In the latest version of vSphere (5), the hypervisor comes in the form of VMware ESXi.

Type 1 and Type 2 Hypervisor:

Hypervisors are generally grouped into two classes: type 1 hypervisors and type 2 hypervisors. Type 1 hypervisors run directly on the system hardware and thus are often referred to as bare-metal hypervisors. Type 2 hypervisors require a host operating system, and the host operating system provides I/O device support and memory management.

VMware ESXi is a type 1 bare-metal hypervisor. (In earlier versions of vSphere, VMware ESX was also considered a type 1 bare-metal hypervisor.) Other type 1 bare-metal hypervisors include Microsoft Hyper-V and products based on the open source Xen hypervisor like Citrix XenServer and Oracle VM.

 

In other words, Type 1 hypervisor runs directly on the hardware; a Type 2 hypervisor runs on operating system.

 

This is a significant difference from earlier versions of the VMware vSphere product suite. In earlier versions of VMware vSphere, the hypervisor was available in two forms: VMware ESX and VMware ESXi. Although both products shared the same core virtualization engine, supported the same set of virtualization features, leveraged the same licenses, and were both considered baremetal installations, there were still notable architectural differences. In VMware ESX, VMware used a Linux-derived Service Console to provide an interactive environment through which users could interact with the hypervisor. The Linux-based Service Console also included services found in traditional operating systems, such as a firewall, Simple Network Management Protocol (SNMP) agents, and a web server.

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Open vSwitch Configuration

Posted: October 12, 2012 in ESX, VM, VMWare
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Hey All,

Found the below link while browsing through the web about Open vSwitch Configuration. It is really well written by Scott Lowe…

Have a look at the below link :

http://blog.scottlowe.org/2012/10/04/some-insight-into-open-vswitch-configuration/

Symptoms:

–          The Server service fails to start and the below events are recorded

Event ID: 7023

Source: Service Control manager

Type: Error

Description: The Server service terminated with the following error: More data is available.

–          Not Enough storage is available to process this command.

Event ID: 7001

Source: Service Control manager

Type: Error

Description: The Netlogon service depends on the server service which failed to start because of the following error: More data is available.

–          System Error 8 has occurred. Not enough storage is available to process this command.

–          If you try to start the Server Service manually, the following errors may occur: A System error has occurred: System Error 234 has occurred.

–          You will not be able to execute any command in the Server.

–          You get error message when you open the Network connections (ncpa.cpl)

Observations:

–          Other services may fail to start because these services are dependent on the Server Service.

–          The Server service queries the registry value above for its entries. The buffer for the amount of information that the Server service can accept when it queries is approximately 32 KB. If there are more than 32 KB in that entry, the Server service will fail to start and return the error “More data is available,” or “Not enough storage is available.”

–          It looks like certain software’s can also cause for this error, those maybe the Norton Antivirus, Acronis trueImage, Seagate DiscWizard, IBM antivirus, Microsoft Bitdefender, Symantec Endpoint Protection or AVG, Try Disabling them or uninstalling and check if the problem persists.

–          You can instantly rectify this error if you restart the server, but the error re-occurs in 2 to 3 days.

Resolution:

PLEASE BACKUP YOUR REGISTRY FIRST BEFORE YOU MAKE ANY CHANGES

This issue may be cause of two reasons, one is the NullSessionPipes and the other is IRPStackSize.

  1. NullSessionPipes

The Cause of these errors is due to too much data stored in the following registry key:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters\NullSessionPipes

The Server service queries the registry value above for its entries. The buffer for the amount of information that the Server service can accept when it queries is approximately 32 KB. If there are more than 32 KB in that entry, the Server service will fail to start and return the error “More data is available,” or “Not enough storage is available.”

The Solution is to remove any unnecessary entries from this value in the registry.

The Default information stored in this key is:

COMNAP

COMNODE

SQL\QUERY

SPOOLSS

LLSRPC

EPMAPPER

LOCATOR

  1. IRPStackSize

Go to the below Registry entry to edit the IRPStackSize

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters

If you do not have the Registry entry then create one manually, but make sure the name should be correct as it is case sensitive.

To create the Registry entry follow the below steps:

–          Open REGEDIT

–          Proceed to the following location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters

–          Click Edit, and point to New and then click DWORD Value

–          Type IRPStackSize , Click Edit and then modify the Value

–          The Value should be 0x00000050 in Hexadecimal or 80 in Decimal. This should resolve your issue, normally values are provided to 1 to 15 in decimal notation. Better if you provide higher value so that the problem doesn’t come back.

–          Restart the Server after the changes are done.