Friday, August 31, 2007

AMD's new Rapid Virtualization Indexing Processors:

Read the full article here.

This is what I'd like to talk about: Memory hardware assists. With the new code-named Barcelona quad-core CPU due to be available in a few weeks with volume shipments in a few months, AMD is going to provide support for what they refer to as "Nested Page Tables" (or NPT for short) which is nothing but memory virtualization support.
A year ago at VMworld 2007 Sr Director R&D Jack Lo provided an illuminating session on the matter: VMware and Hardware Assist Technology (Intel-VT and AMD-V). This session provided a very interesting inside about the mechanisms that VMware is using today in terms of memory virtualization (i.e. Shadow Page Tables) that are basically a software "fake" that allows Guest OS'es to pretend to have full control of the memory address space provided to them while in reality it is the hypervisor maintaining full control of that. In fact if you think about it, in a standard x86 world, only one OS could run on the system and it is that OS keeping control of the hardware resources. In a virtual environment this stack is "screwed up" since the OS doesn't run on real hardware (and there are many OS'es running on the system) so the hypervisor needs to create this software re-mapping of physical resources into the Guest space. Mr. Lo also touched on future hardware assist technologies that should provide a performance boost in this area and AMD NPT was in fact mentioned. The good thing is that "future" at some point becomes "present" and here we are.

The whole idea is that now the processor itself can keep track of these two levels of memory space (i.e. the one that the hypervisor sees and the one that each guest OS sees) without any sort of software remapping being done within the hypervisor as it is the CPU that is able to maintain these multiple mappings onto the registries built into the silicon. What VMware has been suggesting lately is that while their "software binary translation" has better performance than the silicon counterpart Intel-VT and AMD-V for CPU operations, these Nested Page Tables will give a performance boost comparing to their own "software shadow page tables" for memory operations. Without getting into the specifics you should rest assured that VMware is going to intercept NPT support in future releases of the hypervisor in a timely manner. And no, if you were wondering, ESX 3.0.2 (which is the current version as of today) won’t support NPT.

So when is this supposed to show big improvements? As always for performance related things it really depends on what you are doing. For the vast majority of CPU intensive and/or IO intensive workloads NPT won't make much of a difference. There are however some workloads that might gain huge performance benefits. Typically these applications are those with specific memory patterns. This does not necessarily mean virtual machines with big memory footprints but specifically virtual machines with a very high number of "context switches". A occurs whenever a thread needs to leave control to another thread; at the high-level when this occurs the OS needs to save the volatile state of the exiting thread and load the previously saved volatile state of the next thread to be executed. On a standard physical system this is a procedure that the OS handles with the support of the processor while in a virtual environment the Guest OS tries to do the same but instead of getting hardware support to achieve the context switch the hypervisor traps the request and re-works it to fit into the real system resources (well what happens is more complex but you have got the point). This generates overhead especially if you think that you normally get hundreds if not thousands of context switches per second on a Windows system. NPT is all about getting rid of this software re-mapping and allow a much streamlined path from the Guest to the physical resource without the hypervisor acting as the “man in the middle”.

Wednesday, August 22, 2007

Free Chapters of highly anticipated VI3 Technical Design Guide available:

VI3 Advanced Technical Design Guide authors release free sample chapter of their upcoming new book. The MOST popular book on VMware virtualization for the last two years, VMware ESX Server: Advanced Technical Design Guide, is now available for free here. There has been high demand for the release of the new book: Virtual Infrastructure 3: Advanced Technical Design Guide.

The authors: Ron Oglesby, Scott Herold, and Mike Laverick are making three chapters of the new book available NOW FOR FREE! Rush and get your download here!

  • Part 1 - Chapter 4 - VirtualCenter and Cluster Design
  • Part 1 - Chapter 10 - Recovery and Business Continuity
  • Part 2 - Chapter 1 - Installing ESX 3.x

Wednesday, August 15, 2007

Intel Launches Two Xeon Processors For Virtualization

Full original article is located here.

The chips enable third-party virtualization software, such as VMware, to offload workload to the system hardware to boost performance.

Intel on Monday introduced a couple of quad-core Xeon processors with improved virtualization capabilities.

The X5365 and L5335 are for running server and workstation applications. The former is a 3.0-GHz chip that fits inside a 120-watt envelope. The L5335 has a clock speed of 2.0 GHz within a 50-watt envelope. Each chip has a 1333-MHz front-side bus.

Both processors include Intel's Virtualization Technology, which enables third-party virtualization software, such as VMware, to offload workload to the system hardware to boost performance. VT offers 64-bit guest operating system support.

The processors also include new VT extensions for better interrupt handling in virtualization of 32-bit Microsoft(MSFT) Windows. For energy efficiency, the chips have Intel's new "energy smart" technology that lower power use while the chip is idle.

Tuesday, August 14, 2007


A small quote from the full article follows:

Citrix will announce its acquisition of XenSource tomorrow, The Register has learned.

In a bid to expand its software management play, Citrix will grab the developer of the open source Xen hypervisor. The deal will give XenSource heftier corporate backing needed to compete against VMware.

The full article is here.

Monday, August 13, 2007

Good summary of Vmware long term plans (for the IPO investers): has put together a very good summary of long term and upcoming plan that VMware has announced as part of the IPO stock offering this week.

Read all about it here.

Thursday, August 9, 2007

Full details leaked on new ESX 3.1.0 and VC 2.1.0 features: has a scoop on the official new features that will be in the next major VI 3 release later this year.
Quoting from
  • Solid State Drive (SSD) boot support
    As initially discovered last month, VMware will make available a special version of ESX Server (mentioned with terms like ESX Lite and Embedded ESX) for OEM vendors, to be installed into bootable Solid State storage devices (flash drives, etc.). This option will allow creation of ESX Server hardware appliances for easy jumpstart, granting smaller form-factors and improved reliability.
    Dell, IBM and possibly other vendors will offer this option at announcement time in Q3 2007.
  • DMotion
    Unofficially introduced with ESX Server 3.0.1, in its first version DMotion is a special VMotion operation only capable of moving running virtual machines from an ESX Server 2.5.x host to a new ESX Server 3.x., without shared SAN LUN mandatory requirement.
    In ESX Server 3.1 this capability will be extended, allowing hot migration of running virtual machines between ESX 3.1 hosts through the Ethernet cable.
  • Patch management system for host and virtual machines (UpdateManager)
    ESX Server 3.1 will finally introduce an automated patch management system called UpdateManager. This solution will be able to update both host itself and virtual machines (both Microsoft Windows and Red Hat Enterprise Linux).
    UpdateManager will feature security backup before patching and automated rollback if something goes wrong.
  • VMware Consolidate Backup (VCB) and VMware Converter integration
    VirtualCenter 2.1 will now allow restoring VCB images with an integrated version of VMware Converter.
  • Server consolidation advisor
    VirtualCenter 2.1 will expose a server consolidation assistant able to analyze which physical machines should be converted in virtual ones, and where to move existing VMs among available hosts.
    (note that with this feature VMware is further extending competition with PlateSpin, covering both features with PowerRecon and PowerConvert)
  • Guest OS disaster recovery capability
    VirtualCenter 2.1 will be able to recognize a failure inside a virtual machine and restart it through VMware HA module.
  • Power saving capability (Distributed Power Management)
    VirtualCenter 2.1 will introduce a new resources utilization analysis feature, able to verify when a physical host can be powered off, VMotion-ing its virtual machines on other hosts without impacting performances.
  • Support for Cisco Discovery Protocol (CDP)
    VirtualCenter 2.1 will be able to recognize and use CDP to discover physical and virtual network topologies.
    It stays unconfirmed if ESX Server 3.1 will already expose new virtual network architecture, allowing 3rd party virtual switches, as it will be announced by Cisco CEO at VMworld 2007.
  • Support for 10Gbit Ethernet network cards
  • Support for TCP/IP Offload Engine (TOE) network cards
  • Support for network load balancing algorithms
  • Support for 200 hosts and 2000 virtual machines
  • Support for 128GB RAM per host and for 64GB RAM per virtual machine
  • Support for SATA storage devices
  • Support for N_Port ID Virtualization (NPIV)
  • Support for VCB over iSCSI SANs
  • Support for IPv6 in virtual networking
Very Nice KVM tool for VI 3:

This information and original info at

"An unoffical contest has sprung up to create with the VirtualCenter SDK a “MKS Client”. For those not in the know, MKS stands for a Mouse, Screen and Keyboard (you probably know it better as KVM). It’s a process that runs on an ESX host which allows for the redirection of inputs and outputs to the VM’s Remote Console - put simply it allow you interact with the VM using VMware’s client. The contests aim to produce a kind of stripped down client which only allows for this kind of interaction with the need for a full Vi Client. I blogged about Eric Sloof’s creation earlier this week. Anyway, it looks like Bouke Groenescheij and Richard Garsthagen (of VMware EMEA) have joined into this informal contest too…"




Thursday, August 2, 2007

Microsoft and Xen Team up:


Microsoft announced today it will team up with open source virtualization supplier XenSource to run Linux virtual machines under its Windows Longhorn Server.

The move is a big extension of Microsoft's previous commitment to allow Linux virtual machines to run under Windows. In April, it said it would support Linux under its base virtualization product, Virtual Server. Now it's going to support the generation and management of many Linux virtual machines on its most advanced software.


Read the full article here.

Wednesday, August 1, 2007

New ESX 3.0.2 / VC 2.0.2 releases:

Get the new code here.

Bug fix releases and some new extended support.

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