What’s new in Windows Server 2008 R2 Hyper-V Performance and Scale?
When the first version of Hyper-V launched last year we worked really hard to make it a great performing product. From what I’ve heard from all of you we did just that – delivered a great performing product. Now in less than a year we have made great strides. For example when we first shipped we only supported 16 Logical Processors and now we support 64! We have also improved the Hypervisor, Networking, Storage, and even added Live Migration.
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.
Virtualization Feature |
Virtual Server 2005 R2 |
WS08 + RTM Hyper-V |
32-bit Virtual Machines |
Yes |
Yes |
64-bit Virtual Machines |
No |
Yes |
Multi Processor Virtual Machines |
No |
Yes, 4 core VMs |
Virtual Machine Memory Support |
3.6GB per VM |
64GB per VM |
Managed by System Center Virtual Machine Manager |
Yes |
Yes |
Support for Microsoft Clustering Services |
Yes |
Yes |
Host side backup support (VSS) |
Yes |
Yes |
Scriptable / Extensible |
Yes, COM |
Yes, WMI |
User Interface |
Web Interface |
MMC 3.0 Interface |
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.
Virtualization Feature |
WS08 + RTM Hyper-V |
WS08 SP2 Hyper-V |
Windows Server 2008 R2 Hyper-V |
Logical Processor Support |
16 |
24 |
64 |
Total number of powered on VM’s |
128 |
192 |
384 |
Total Virtual Processors Supported |
128 |
192 |
512 |
Guest Virtual Processor Support |
4 (WS08 only) |
4 (WS08 only) |
4 (Win7/WS08) |
Address Space Management |
Software Only |
Software Only |
Hardware where available (EPT on Intel and Rapid Virtualization Indexing on AMD) |
Core Parking / Deeper Sleep States (C3) |
No – Limited C states |
No – Limited C states |
Yes |
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.
Virtualization Feature |
WS08 + RTM Hyper-V |
WS08 SP2 Hyper-V |
Windows Server 2008 R2 Hyper-V |
IPv6 offloads |
No |
No |
Yes |
LSOv2 |
Limited (LSOv1 from VM) |
Limited (LSOv1 from VM) |
Supported |
Guest to guest throughput |
Good |
Good |
Better |
VMQ |
No |
No |
Yes – Off by default |
Chimney |
No |
No |
Yes – Off by default |
Jumbo Frames |
No |
No |
Yes |
Virtual Switch MAC learning |
Good |
Good |
Better (every packet) |
Virtual NIC interrupts |
VP0 |
VP0 |
VP0 receive / distributed for send |
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.
Virtualization Feature |
WS08 + RTM Hyper-V |
WS08 SP2 Hyper-V |
Windows Server 2008 R2 Hyper-V |
Dynamic VHD Performance |
Writes 3x slower than fixed. This is due to limited meta data caching. |
Writes 3x slower than fixed. This is due to limited meta data caching. |
Dynamic and Fixed Disk performance at almost parity |
Diff Disk Scaling Performance |
1x |
1x |
4x – 5x |
IO Sizes (Virtual SCSI) |
64KB |
64KB |
8MBytes (improves throughput) |
IO Size (Virtual IDE – no changes just for comparison) |
64KB |
64KB |
64KB |
VHD Block Size |
512KB |
512KB |
2MB |
Fixed VHD Creation Speed |
1x |
1x |
3x – 4x |
Hot add of storage |
No |
No |
Yes |
SCSI Command Pass-through |
No |
No |
Yes |
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.
Virtualization Feature |
WS08 + RTM Hyper-V |
WS08 SP2 Hyper-V |
Windows Server 2008 R2 Hyper-V |
Moving Virtual Machines |
Quick Migration |
Quick Migration |
Live Migration |
VDI |
No |
No |
16 Node x 64 VM |
NUMA |
Ok placement – stack on Node 0 |
Ok placement – stack on Node 0 |
More even distribution |
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)
Comments
Anonymous
September 08, 2009
Can you point us at full specs for the Hyper-V virtual switch - e.g. how many MAC addresses can it learn, how many vlans supported (most physical switches don't support all 4094 at once) - and which features are dependent on NIC/driver support to workAnonymous
October 12, 2009
I'm happy about the improvements but why is it that we can't boot from a SCSI VHD as we're told that IDE is basically the same, but the performance of SCSI VHDs has been improved.