Who knows... maybe I'll pick this blog up again in the future.

(click the image above to see the presentation deck)

So what are RemoteFX and Dynamic Memory? 

RemoteFX is the next step in plumbing direct access to hardware in Virtual Machines (VM).  Today Hyper-V gives direct access to disk (passthrough disks) and networking (VMQ and WinSockDirect).  What is new with RemoteFX is the tie to hardware is even deeper for graphics.  For example RemoteFX allows you to create and run a DirectX Shader in your VM.  Having this level of graphics control and power in a VM while sharing "real graphics hardware" across VM's on the host will enable all kinds of new applications to be virtualized.  You can read more on it @ RemoteFX.

Dynamic Memory (DM) is a new feature that will allows greater consolidation of VM's.  DM will aide VM consolidation by allowing physical host memory to be shared between VM's.  While the total memory used across VM's can appear to exceed total host physical memory it is actually in one of two categories - "free - ie its all zeros" or "physcial- meaning it is backed by a host physical page".  So how is this different from what Hyper-V could do before?  In previous versions of Hyper-V (Windows Server 2008 (SP1 / SP2 / R2) you have to statically set the amount of memory a VM would use before you start it.  For example you might set 2GB for a Server VM.  Now with Dynamic memory you get to set an initial value like 1GB and a maximum of 4GB.  As more VM's run on a host Hyper-V will look to see which VM's are most memory contrained and "borrow" memory from one VM's to give to another.  From the perspective of the VM it just looks like the System is using more memory where in fact the memory the system is reporting as used is no long backed by phsical memory in the host.  It is just a holding place.  At some future point I might go into more on how DM actually works and some of its balancing goals however today was you to let you know it is out there.  You can also read more @ Hyper-V Dynamic Memory Evaluation Guide

So where can you get these new features?  These new features are available in Windows Server R2 SP1 and Windows7 SP1.  Today you can only download the RC (https://technet.microsoft.com/en-us/evalcenter/ff183870.aspx) however keep a look out for the final release of SP1.

  Enjoy,

     Tony Voellm

A SAP on Hyper-V paper was just brought to my attention. It has a very good overview of Hyper-V and how it benefits SAP,  The document focuses on getting SAP running well in Hyper-V and has lots of great technical information.  One thing I wish the paper had was solid performance data showing how the suggestions help improve performance and what the overhead is when going from physical to virtual.  Even without that the paper is a good read.

  Enjoy,

    Tony

https://blogs.msdn.com/b/saptech/archive/2010/04/29/new-best-practices-for-sap-on-hyper-v-white-paper-available.aspx

https://download.microsoft.com/download/0/7/7/0778C0BB-5281-4390-92CD-EC138A18F2F9/WS08_R2_VHD_Performance_WhitePaper.docx

  Enjoy,

     Tony

iSCSI 10 Gigabit Ethernet Performance Tuning With Windows Server® 2008, Hyper-v and the NetApp FAS® 3070

https://download.microsoft.com/download/F/B/3/FB38CA2C-6694-4D25-8452-4A28668A87F2/MSFT-NetApp-10G.docx

This paper has a really good overview of storage solutions and performance comparison graphs.

Enjoy,

    Tony

Anthony F. Voellm (aka Tony)

12/17/2009

https://blogs.msdn.com/tvoellm

This FAQ is titled R2 since it updates the original FAQ as of the Windows Server 2008 R2 Hyper-V.  Since Hyper-V originally released we have continued to improve it.  We have new features in R2 like Live Migration, support for 64 processors and lots of improvements in networking and storage. 

******************************************************************************

Contents

· Q: Is there a place that compares features and versions of Hyper-V?

· Q: What is the recommend configuration for performance testing?

· Q: How do I monitor performance?

· Q: Is there any “official” documentation for Hyper-V performance counters?

· Q: Are there any official virtualization benchmarks I can use to compare machines and virtualization solutions?

· Q: Is there any common terminology used to talk about virtual machine configurations?

· Q: How much memory should I reserve for the root?

· Q: Are there any services that should be stopped?

· Q: Is it ok run applications / processes in the root OS?

· Q: Is there a simple way to disable the hypervisor to run some baseline tests on the native system

· Q: Should I use passthrough disks or iSCSI attached to the guest for storage?

· Q: Are there ways to reduce overall networking overhead?

· Q: Are there additional knobs for performance nuts?

· Q: Are their additional resources that are useful for understanding Hyper-V?

******************************************************************************

Q: Is there a place that compares features and versions of Hyper-V?

A: https://blogs.msdn.com/tvoellm/archive/2009/08/05/what-s-new-in-windows-server-2008-r2-hyper-v-performance-and-scale.aspx

Q: What is the recommend configuration for performance testing?

A: Here are some simple steps:

1. Be sure to have the latest WS08 Hyper-V build – Windows Server 2008 R2 is the current verion.

2. Next you need to make sure you are running a “Supported OS” with the latest Service Packs installed on the guest OS.  For the latest on which OS are supported and the number of virtual processors that can be used see https://support.microsoft.com/kb/954958

3. Make sure the guest and root OS have integration components installed (https://blogs.msdn.com/tvoellm/archive/2008/04/19/hyper-v-how-to-make-sure-you-are-getting-the-best-performance-when-doing-performance-comparisons.aspx **and** https://blogs.msdn.com/tvoellm/archive/2008/01/02/hyper-v-integration-components-and-enlightenments.aspx )

4. Make sure you are using the “Network Adapter” and not the “Legacy Network Adapter”. The legacy adapter uses emulation which creates additional CPU overhead.

5. Use pass-through disks attached to SCSI for the best performance. Next best is Fixed VHD attached to SCSI. To understand storage better see (https://blogs.msdn.com/tvoellm/archive/2007/10/13/what-windows-server-virtualization-aka-viridian-storage-is-best-for-you.aspx )

6. Follow these tips for avoiding pitfalls https://blogs.msdn.com/tvoellm/archive/2008/04/19/hyper-v-how-to-make-sure-you-are-getting-the-best-performance-when-doing-performance-comparisons.aspx

Q: How do I monitor performance?

A: First you need to understand that the clocks in the root and guest Virtual Machines may not be accurate See (https://blogs.msdn.com/tvoellm/archive/2008/03/20/hyper-v-clocks-lie.aspx ). Given an understanding of clocks you can see why we implemented the “Hyper-V Hypervisor Logical Processor” performance counters (access using perfmon) which are not skewed by clock effects. There are other Hyper-V performance counters that are useful. See the following for more details (https://blogs.msdn.com/tvoellm/archive/tags/Hyper-V+Performance+Counters/default.aspx )

There is also a detailed posting on how to monitor Hyper-V performance at https://blogs.msdn.com/tvoellm/archive/2009/04/23/monitoring-hyper-v-performance.aspx

Q: Is there any “official” documentation for Hyper-V performance counters?

A: As of the writing of this blog there is no “official” documentation. However you can find documentation on my blog here https://blogs.msdn.com/tvoellm/archive/tags/Hyper-V+Performance+Counters/default.aspx .

Q: Are there any official virtualization benchmarks I can use to compare machines and virtualization solutions?

A: There are no official and widely accepted benchmarks.  That said, Intel put together a benchmark called vConsolidate and the SPEC group is working on SpecVirt.

Q: Is there any common terminology used to talk about virtual machine configurations?

A: Yes - Internal to Microsoft we typically use the following;

· Native = System without the Hyper-V role. This means you have no virtual drivers, virtual switch, …

· Root = Most people call this the host however we refer to the management partition of Hyper-V as the root because it is technically not a hosted VM solution.  You can also think of this as the OS that boots Hyper-V and handles the management of VMs, devices, memory and other share VM resources.

· Guest = Guest Virtual Machine.

· 8p.child.2x1p or better 8p.child.2VMx1VP = A system with 8 logical processors / cores running 2 Virtual Machines (VM) each with 1 Virtual Processor (VP)

Q: How much memory should I reserve for the root?

A: There is a good discussion on how much memory to leave for root in the “Windows Server 2008 Tuning Guide.” You can find it here https://www.microsoft.com/whdc/system/sysperf/Perf_tun_srv.mspx. The relevant section from the guide is as follows:

Correct Memory Sizing

You should size VM memory as you typically do for server applications on a physical machine. You must size it to reasonably handle the expected load at ordinary and peak times because insufficient memory can significantly increase response times and CPU or I/O usage. In addition, the root partition must have sufficient memory (leave at least 512 MB available) to provide services such as I/O virtualization, snapshot, and management to support the child partitions.

A good standard for the memory overhead of each VM is 32 MB for the first 1 GB of virtual RAM plus another 8 MB for each additional GB of virtual RAM. This should be factored in the calculations of how many VMs to host on a physical server. The memory overhead varies depending on the actual load and amount of memory that is assigned to each VM.

Q: Are there any services that should be stopped?

A: Not if you are running Server Core which is the ideal root OS to use. Regardless of running server core vs full server you should close the Hyper-V Management Console because it has a noticeable impact on CPU. If you want the details see https://blogs.msdn.com/tvoellm/archive/2008/04/19/hyper-v-how-to-make-sure-you-are-getting-the-best-performance-when-doing-performance-comparisons.aspx

Q: Is it ok to run applications / processes in the root OS?

A: You should avoid running any Role / Feature or custom service in the root. If you have services you want to run put them in a guest VM. Running roles in the root can have a negative impact on the guest VM’s. This is due to how the Hypervisor scheduler handles the root virtual processors.

Note: Outside pure performance deploying applications in the root has licensing implications as in a virtualized environment the so called virtual use rights only allow to run virtualization itself (and its associated management like management agents etc) in the physical environment. More information can be found at:

· Windows Server 2008 R2 Licensing overview - look for Virtual Use Rights

· Windows Server 2008 Licensing Overview (Pdf)

Q: Is there a simple way to disable the hypervisor to run some baseline tests on the native system.

A: Yes. “bcdedit /set hypervisorlaunchtype off” and reboot the server. You should also consider changing the protocols on the root network device to re-enable TCP/IP and turn off the “Microsoft Virtual Network Switch Protocol”.

To turn it back on do “bcdedit /set hypervisorlaunchtype on” and reboot the server.

Q: Should I use passthrough disks or iSCSI attached to the guest for storage?

A: The decision depends on what features you need to expose to the guest. In the passthrough case the drive will show up without knowledge of the underlying LUN.

Educated guess: If you are looking for raw performance passthough will give you the best result.

Reason: When doing IO from the guest using passthough you traverse the guest storage stack + disk stack in the root. When doing iSCSI you traverse the storage + networking stack in the guest + root networking stack

Q: Are there ways to reduce overall networking overhead?

A: The way to reduce storage overhead (ie adding CPU use) is to use passthrough disks. There are also ways to reduce networking overheads by using two new features in R2. One feature is called Virtual Machine Queues (VMQ) and the other is called Chimney Offload. VMQ reduces overheads by reducing the cost of routing incoming packets, more optimized copy paths, and better interrupt distribution. Chimney offload is helpful for long running connections. It also improves overhead by reducing copy path costs. The challenge is that no networking devices I’ve seen support both of these features. Typically they support VMQ or Chimney offload.

If you have a device that supports one of these features the following article will help you configure it:

Networking Deployment Guide: Deploying High-Speed Networking Features

https://download.microsoft.com/download/8/E/D/8EDE21BC-0E3B-4E14-AAEA-9E2B03917A09/HSN_Deployment_Guide.doc

Q: Are there additional knobs for performance nuts?

A: We are trying to make Hyper-V knob-less. However we are engineers and here are some tips.

1. Remove the CDROM drive from the guest if you don’t need it

2. Look into the Caps / Weights / Reserves in the CPU config. You can use these to “balance” workloads.

3. You can use the WMI interfaces to force a VM to a particular node (https://blogs.msdn.com/tvoellm/archive/2008/09/28/Looking-for-that-last-once-of-performance_3F00_-Then-try-affinitizing-your-VM-to-a-NUMA-node-.aspx) Hyper-V does not guarantee node affinity for VP’s but it does for memory. There is a good chance the VP’s will stay on the node because the scheduler is NUMA aware.

Q: Are their additional resources that are useful for understanding Hyper-V?

A: Yes – here is a list

• https://technet.microsoft.com/en-us/dd565807.aspx
• https://blogs.technet.com/virtualization
• https://blogs.technet.com/windowsserver/default.aspx
• https://blogs.technet.com/winserverperformance
• https://blogs.msdn.com/virtual_pc_guy/
• https://blogs.technet.com/jhoward/
• https://blogs.msdn.com/tvoellm

I've changed the name of the blog to "All topics fundamentl" to reflect some of the expanded entries you will see around Reliability, Security and Privacy.  Together with performance these entries will help you have an even better Windows Experience.

 Enjoy.... Tony

This blog post is designed to help you understand what has changed in terms of performance and scale of the product. 

A note on the releases

As you look at this blog entry please take special note to SP1, SP2 and R2. 

Here are the product names and the version of Hyper-V -

Windows Server 2008 RTM – This included only the Beta version of Hyper-V

Windows Server 2008 RTM + KB 950050 – This was the first RTM release of Hyper-V and shipped in June 2008.  We’ll call this WS08 + RTM Hyper-V in the tables below.

Windows Server 2008 SP2 – This is the bug fix release of Hyper-V plus improvements for performance and scale and was released in April 2009

Windows Server 2008 R2 – This is the latest release of Hyper-V and was announced in July 2009.

Comparison of Virtual Server and Windows Server 2008 SP1 Hyper-V

So lets start at the beginning of Microsoft’s virtualization products and that is Virtual Server.  Virtual Server was the first virtualization solution and worked with Windows Server 2003 [R2].  Virtual Server as a VMM solution and was replaced in Windows Server 2008 by Hyper-V a Hypervisor based solution.  You can see in terms of scale in Hyper-V we added Multi-VP support, 64 bit, and large memories.

Hypervisor improvements from Windows Server 2008 SP1 Hyper-V to Windows Server 2008 R2 Hyper-V

Once we moved in to the world of Hyper-V with Windows Server 2008 SP1 we had a mini-release with SP2 and now have R2.  In the tables below you will see how the performance and scale has evolved.

This table details the changes at the kernel and hypervisor level – Notice the changes in number of Logical Processors (LP), Virtual Processors (VP), and Virtual Machines (VM) counts along with hardware feature adoption.

Networking improvements from Windows Server 2008 SP1 Hyper-V  to Windows Server 2008 R2 Hyper-V

This table details changes in networking.  Notice the improved support for IPv6 and new hardware features like Virtual Machines Queues (VMQ) which helps with receive scaling and Chimney (TCP/IP offload into hardware) which helps with latency.

Storage improvements from Windows Server 2008 SP1 Hyper-V to Windows Server 2008 R2 Hyper-V

The following table shows changes in storage.  Some of the changes are performance related like hot add of storage.  This helps performance by reducing the time it takes to add new storage.  The big things to note are increases in IO Sizes passed from VM’s and huge improvements in Dynamic VHDs.

Storage improvements from Windows Server 2008 SP1 Hyper-V to Windows Server 2008 R2 Hyper-V

This last table shows some of the top level virtualization feature improvements effecting the whole system.

As you can see we made numerous improves in all the core areas while at the same time adding new functionality.  Hope you enjoy the new release!

  Enjoy,

  Anthony F. Voellm (aka Tony)

A tool like IOMeter [from www.iometer.org] can be programmed with the mixes of reads/wrtes and sequential/random IO's detailed below.

Workload Category	I/O Size	Percentage of READ vs. WRITE	Percentage of RANDOM vs. SEQUENTIAL
Web File Server	4KB	95% RD vs. 5% WR	75% RAND vs. 25%  SEQ
Web File Server	8KB	95% RD vs. 5% WR	75% RAND vs. 25%  SEQ
Web File Server	64KB	95% RD vs. 5% WR	75% RAND vs. 25%  SEQ
Decision Support System DB	1MB	READ	RANDOM
Media Streaming	64KB	98% RD vs. 2% WR	SEQUENTIAL
SQL Server Log	64KB	WRITE	SEQUENTIAL
OS Paging	64KB	90% RD vs. 10% WR	SEQUENTIAL
Web Server Log	8KB	WRITE	SEQUENTIAL
OLTP DB	8KB	70% RD vs. 30% WR	RANDOM
Exchange Server	4KB	67% RD vs. 33% WR	RANDOM
Workstation	8KB	80% RD vs. 20% WR	80% RAND vs. 20% SEQ
Video on Demand	512KB	READ	RANDOM

 Enjoy - Tony Voellm