For those propeller heads who wants to know what a SLAT is, read on….

SLAT stands for “Second Level Address Translation”. SLAT is a new feature in today’s CPU on top of Virtualization support (Intel-V, AMD-V etc) to improve VM performance while reducing processing load on the hypervisor by removing the need for the hypervisor to maintain shadow page tables for each VM mapping virtual memory to physical memory.

So, ever thought about what happens when you move or migrate a VM from a host with SLAT support to another one without?

Answer is “Nothing”. You’ll obviously notice a slight performance degradation due to higher overhead on the receiving hosts’ hypervisor, but there won’t be any impact on its functionality.

Haven’t you heard about chimney which work as an exhaust in traditional Kitchens and factories?

Now one of the virtual networking features of Hyper-V in Windows Server 2008 R2 is using this word as “VM Chimney” - may be MS wants to emphasize that you got an easy path to flow. Anyway, VM Chimney in Hyper-V allows a VM to offload its network processing load onto the NIC of the host computer. This is something similar to TCP offload scenario, Hyper-V simply extends this functionality into the virtual world. This benefits both CPU and overall network throughput performance, and it is fully supported by Live Migration.

VM Chimney is disabled by default in Windows Server 2008 R2, primarily for compatibility reasons. Vendors like Intel, supports the compatibility for VM Chimney and if you are sure that the hardware you purchased support this – TURN IT ON for a better host system performance and a simultaneous boost to VM network throughput.

Support for Jumbo Frames was first introduced in initial release of Windows Server 2008 to support the hardware and now the same has been extended to support VMs. So, just like improving performance on hardware level, Jumbo Frame capability for VMs now can increase the performance of virtual networking and provides 6 times larger payloads per packet, which improves not only overall throughput but also reduces CPU utilization for large file transfers.

Do you know how different virtualization tower maps to their respective products? if not, read on…

No bias intended, but I selected Microsoft because they have clearly aligned their products to different virtualization tower as below:

• Presentation Virtualization – Windows Server 2008 R2 Remote Desktop Services (formerly, Terminal Services)
• Server Virtualization – Windows Server 2008 Hyper-V, Hyper-V Server, Virtual Server 2005 R2 SP1
• Desktop Virtualization – Virtual PC, Virtual Desktop Interface
• User State Virtualization – Document Redirection, Offline Files
• Application Virtualization – Microsoft APP-V (streams the application over the internet or intranet)
• Storage Virtualization – Data Protection Manager, Windows Storage Server

KB950050
Description: Hyper-V RTM
Date: June 26, 2008
Mandatory?: Yes
File Name: Windows6.0-KB950050-x64.msu
On Windows Update?: Yes
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KB956710
Description: Hyper-V update : 24 proc and 192 VM possible
Date: Sept 23, 2008
Mandatory?: Yes, if host has > 16 Logical processors
File Name: Windows6.0-KB956710-v2-x64.msu
On Windows Update?: No
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KB956589
Description: Resolve potential issues when you manage Hyper-V with SCVMM
Date: Sept 23, 2008
Mandatory?: Yes if SCVMM 2008 is used to manage environment
File Name: Windows6.0-KB956589-x64.msu
On Windows Update?: No
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KB956774
Description: Resolve the scenario where a BITS client cannot handle files that have paths that contain the volume GUID in Windows Server 2008.
Date: Sept 23, 2008
Mandatory?: Yes if GUIDs are used to access instead of drive letter or mount point
File Name: Windows6.0-KB956774-x64.msu
On Windows Update?: No
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KB956697
Description: Resolve an issue in which the Hyper-V Volume Shadow Copy Service (VSS) does not back up virtual machines properly
Date: Sept 8, 2008
Mandatory?: Yes, any time VSS is utilized for backups
File Name: Windows6.0-KB956697-x64.msu
On Windows Update?: Yes
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KB951308
Description: Increased functionality and virtual machine control in the Windows Server 2008 Failover Cluster Management console for the Hyper-V role
Date: Sept 11, 2008
Mandatory?: Yes, for Failover Clustering
File Name: Windows6.0-KB951308-v2-x64.msu
On Windows Update?: No
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KB953828
Description: The NLB host does not converge as expected on Windows Server 2008 Hyper-V virtual machines
Date: June 25, 2008
Mandatory?: Yes if NLB is in use
File Name: Windows6.0-KB953828-x64.msu
On Windows Update?: No
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KB953585
Description: Error message when you try to start a Hyper-V virtual machine on a Windows Server 2008 computer that uses the NUMA architecture.
Date; Sept 4, 2008
Mandatory?: Yes if NUMA hosts are in use
File Name: Windows6.0-KB953585-x64.msu
On Windows Update?: No
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KB950182
Description: A computer that is running an x86-based version of Windows Server 2008 or an x86-based version of Windows Vista may use fewer processors than expected if the number of cores on a socket is not a power of 2
Date: April 11, 2008
Mandatory?: Yes, if you wish to start a Windows Server 2008 x86-based virtual machine on a computer that uses a 6-core processor.
File Name: Windows6.0-KB950182-x86.msu
On Windows Update?: No
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KB957967

Description: Stop error message on a Windows Server 2008-based computer that has the Hyper-V role installed: "STOP 0x0000001A"
Date: October 8, 2008
Mandatory?: No
File Name: Varies
On Windows Update?: No
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KB958065

Description: You cannot configure a Hyper-V virtual machine by using Windows Server 2008 Failover Clustering when the virtual machine uses a storage device that is managed by a third-party clustered file system or a third-party replication solution
Date: November 3, 2008
Mandatory?: Yes, if you use 3d-party clustered file systems to store few VMs per LUN, running on different hosts.
File Name: Varies
On Windows Update?: No
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KB957967

Description: Stop error message on a Windows Server 2008-based computer that has the Hyper-V role installed: "STOP 0x0000001A"
Date: October 8, 2008
Mandatory?: No, apply this hotfix only to systems that are experiencing this specific problem.

File Name: Vid.sys
On Windows Update?: No

Microsoft's Virtualization Software Hyper-V has finally been RTM'd and available for download from here