Xen

Get virtual with Sid Smith

Looking for another expert perspective on server virtualization? Sid Smith, who runs the Daily Hypervisor, now has a new blog here on IT Knowledge Exchange.

Virtualization with Sid Smith will focus on the storage, networking and other issues related to deploying and managing VMware, Hyper-V and Xen environments. His first post is about upgrading from ESX to vSphere.

In addition to writing for two blogs, Smith is also a senior systems engineer with VIRTERA, a New York-based solutions provider, and the author of an upcoming book on virtualization. He’s been working in virtualization for nearly a decade, so check out what he has to say.

Oracle beefs up virtualization offering with management capabilities

I have to admit that I have been less than kind when it comes to Oracle’s virtualization software and licensing policies; I’ve written articles about their stubborn refusal to support their customers who use VMware, user frustrations with their licensing policies, and their unsubstantiated performance claims about Oracle VM being three times faster than other server virtualization software.

But, the newly released Oracle Enterprise Manager 10g Release 5 (10gR5) includes a VM Management Pack for Oracle VM that gives people using Oracle VM competitive features like high availability, lifecycle automation and application relationship management, making it a more attractive virtualization option.

Oracle’s Xen-based hypervisor runs on x86-64 Intel- and AMD- based systems and can support any operating system that runs on those platforms. Oracle officially certifies Linux and Microsoft Windows to run as a guest OS. The Oracle VM management tool (Oracle VM Manager) comes in the form of a Web-based interface that manages virtual server pools and performs tasks like live migrations.

The Oracle VM Management Pack 10gR5 gives users a way to manage their physical and virtual environments from one console. Some features include diagnostics of whether a problem is due to an application component, a virtual machine or physical resource issue and built-in configuration management that gives IT a way to track application relationships and analyze configuration changes.

The new management pack also lets you assign specific policies for virtualization, automated deployment through Oracle VM Templates for packaged applications, middleware, database, and Oracle Enterprise Linux. There are also lifecycle automation features for testing, deployment, patching and maintenance capabilities, including automated patching of operating systems and Oracle software running inside the guest VMs.

Lastly, Oracle VM users can now get high availability with new features that allow for server pooling, automatic load balancing and server failover. Many analysts say high availability is an absolute necessity when it comes to virtualization, so it’s great that Oracle decided to add that feature.

Perhaps I should start considering Oracle VM a contender in the virtualization market, especially against Microsoft Hyper-V, which doesn’t even have live migration yet. Or maybe not. Either way, it is an option.

If you run a ton of Oracle apps and you want to give Oracle VM a shot, it is free to download form their website. Oracle VM support per two-socket server costs $599, and includes access to software and updates through the Unbreakable Linux Network and 24X7 support. Oracle VM Premier Support costs $1,797 per two sockets for three years, and includes network access plus 24×7 support.

Xen version 3.3 enhances performance, scalability to open source hypervisor

Xen.org announced the release of a new version of the project’s open source hypervisor, Xen 3.3 today, with enhancements to security, performance and scalability.

The release is now available for download from the Xen.org community site and is the product of a distributed development effort by senior engineers from more than 50 hardware, software, and security vendors.

The new Xen 3.3 release provides users with the new features including:

* Power management in the hypervisor
* Hardware Virtual Machine (HVM) emulation domains for better scalability, performance and security
* Shadow pagetable improvements for the best HVM performance ever
* Hardware Assisted Paging enhancements
* Device passthrough enhancements
* CPUID feature levelling that allows safe domain migration across systems with different CPU models (within the same vendor brand - Intel or AMD)

Xen 3.3 provides virtualization for x64, IA64 and ARM-based platforms, and through close links with CPU and chipset vendors in the Xen project, Xen 3.3 also supports the latest hardware virtualization enhancements, like Intel Virtualization Technology (Intel-VT).

With Xen’s memory ballooning feature, the hypervisor can reallocate memory between guest Virtual Machines (VMs) to guarantee performance and allow greater density of VMs per server. Xen 3.3 also offers CPU portability to allow live migration of VMs across different CPUs, active power optimization to reduce server power consumption, and significant security enhancements.

Simon Crosby, CTO, Virtualization and Management Division, Citrix Systems, said in a statement, “In just two years, Xen has rapidly gained share in virtualization, much as Linux did in operating systems - and in the same period Xen has driven the price of competing hypervisors to zero, allowing any vendor to include virtualization for free.”

In addition to its growing development community, Xen hypervisor is the standard virtualization platform used by cloud computing providers like Amazon.com. It is also used in virtualization products from Citrix (XenServer), Fujitsu, Novell, Oracle (Oracle VM), Sun Microsystems (Sun xVM), and Virtual Iron, and is available as an embedded option in many x86 servers.

Optimizing operating systems for virtual hosts

By eliminating wasteful resource use on your host servers, you can make more resources available for additional virtual machines.

Most operating systems today have been developed to run on physical servers in non-virtual environments. Because all the virtual machines are competing for the same resources on the host server, you want to limit the guest operating system so it only consumes resources that it needs to perform whatever function that it has been designated to do.

Microsoft Windows is notorious for wasting server resources in its typical default configuration. Many unnecessary services are loaded that most servers do not need: for example, when’s the last time you needed the Windows Audio, Print Spooler and Wireless Configuration services on your SQL Server? Windows also constantly reads and writes to disk for things like swap and log files and Windows networking tends to be very chatty on a network often generating excessive network traffic.

All of these additional services generate excessive and often unnecessary network, CPU, memory and disk resource usage. It may not be all that much on any one individual server, but add that up across 12 virtual machines on a host and it makes a difference.

Windows Server 2008 takes a step in the right direction with its Server Core installation which strips out many of the unneeded components including the GUI. Many Linux distributions are already optimized to perform specific functions as well. Additionally, there are many virtual appliances available that have very small footprints and make for good alternatives to full-blown operating systems.

Here are some tips for reducing the amount of resources that your servers consume:

• Keep event and audit logging to a minimum
• Disable unnecessary Windows services
• Disable unneeded network protocols
• Disable screen savers and visual effects
• Remove any unneeded applications
• Remove all unneeded hardware from the virtual machine configuration
• If the server was a physicla-to-virtual (P2V) converstion, delete any non-present hardware
• Optimize anti-virus confgurations to exclude specific directories or disable real time scanning
• Disable NTFS last accessed time stamp
• For Linux systems, disable unneeded daemons, services and background tasks and do not run X-Windows if possible.

In the future, operating systems will evolve to become specifically optimized to run on virtual servers. Until then you should take steps to ensure that your guest servers are optimized to run on virtual hosts.

When not to treat VMs like physical servers

A general rule of thumb in virtual environments is to always treat virtual machines the same as you would physical servers. While this rule holds true in many cases, IT administrators should be aware of some exceptions to this rule. Let’s go over some reasons that you would not treat your virtual machines like physical servers:

• Patching – You should apply all the same operating system and application patches to a virtual machine as you would a physical server. However it is best to stagger your patch deployments so you do not patch and restart all of your virtual machines at the same time. If you did this concurrently you can cause excessive resource utilization on your host servers which could impact other virtual machines running on the host.
• Securing – Secure the virtual machine operating system as you would physical servers, in addition you should ensure that you have proper security setup on the host server’s management console that allows access to the VM as well as on the virtual machine files located on the host server’s disk system. It does no good to have tight security inside your VM and have weak security outside.
• System Monitoring – This is one area that can be very different for virtual servers. There is no need to monitor virtual machine hardware, if you have converted physical servers to virtual machines you should make sure you un-install any hardware management agents from them. In addition virtual machines boot much faster then physical servers. Because of this, many monitoring systems will not detect server re-boots because the boot process happens quicker then the monitoring interval. You may find that you need to adjust your polling interval for virtual servers so you can detect the faster re-boots.
• Performance Monitoring – Another area that is very different from physical servers. Traditional operating system performance reporting tools are often inaccurate when used on virtual machines because they are unaware of the virtualization layer and the underlying physical hardware. You should always use virtual server specific reporting tools to accurately measure performance on virtual machines.
• Anti-virus – Make sure you install anti-virus software on all your virtual machines the same as physical servers. Again one thing to be careful of is to stagger any on-demand scans and definition updates as to not overwhelm the host server. Having all your VMs running a full scan at the same time can completely bog down a host server.
• Backups – It’s OK to backup your virtual machines using traditional operating system backup agents. Always make sure you do not backup too many VMs on a single host at the same time. There are more efficient ways to perform backups in a virtual environment that you may look into to either complement or replace traditional backup methods.
• Disk defragging – You should periodically defrag virtual machine disks using traditional operating system tools for maximum performance. However be careful not to defrag a VM that has a snapshot running, doing this can cause the snapshots rapidly grow in size and degrade host performance. As usual do not defrag more then one VM on a host at a single time because of all the excessive disk activity that is causes.

Be careful not to do too many of the same operations concurrently. With physical servers, only a single server is effected, but in virtual environments many other servers running on a host server can be impacted.

Performance management’s next frontier

Megan Santosus is a features writer for SearchServerVirtualization.com.

VMware Inc.’s recent acquisition of B-hive Networks is indicative of just how much of a wrench virtualization has thrown into the performance management arena. (To recap: B-hive’s Conductor software monitors application performance across virtual environments.) “First and foremost, the acquisition shows the importance of being able to manage performance in a virtualized environment,” said Trevor Matz, the president and CEO of Aternity Inc., a provider of end-user performance management software. “The system metrics normally associated with performance tools are pretty meaningless in virtual environments.”

Traditional performance metrics — CPU, memory usage — that are used to monitor the performance of the hardware that provides service to end users don’t have much relevance in virtual environments, Matz said. “Those metrics are associated with a host machine or virtual box itself and don’t indicate what the end user is experiencing,” he added.

Matz said that Citrix Systems Inc., Microsoft and Parallels are all at work on creating tools that collect meaningful metrics in a virtualized environment. “Having comprehensive tools is not enough,” Matz said, adding that there are already more than enough metrics to parse through. “The next big frontier is the ability to transform huge amounts of data into actionable business intelligence that correlates across platforms.”

Symantec, Citrix take on VMware with block storage management product

On Monday, June 9, Symantec Corp. of Cupterino, Calif., announced the release of Veritas Virtual Infrastructure (VxVI), a server and storage virtualization product built on Citrix Systems Inc.’s XenServer technology. By exploiting Veritas’ block storage management model, VxVI hopes to compete with VMware-Infrastructure-3-in-production environments by offering increased capabilities for storage and availability-critical systems.

The new Xen-based virtual infrastructure platform from Symantec provides storage management and high availability with cross-platform connectivity for the virtual data center. It’s essentially XenServer with the Veritas storage management layer on top — all wrapped in a Symantec management console.

According to Symantec Senior Vice President of Storage and Availability Management Rob Soderbery, the time is right for a product that addresses the needs of testing and development, needs that have been underserved by VMware. “Users understand the storage management challenges with VMware,” he said. Symantec has delivered something “fundamentally new” in how server virtualization works with storage management, he noted.

The key difference between VMware and Veritas is in how each handles virtual machines (VMs). Soderbery argues that the Virtual Machine File System (VMFS) file-based system that VMware uses can’t compete with the block storage system of Veritas VxVI.

As enterprises build out the x86 data center, Symantec’s product seeks to serve those who want to bring physical capabilities into the virtual environment. Veritas Virtual Infrastructure brings dynamic storage layouts, enclosure and array mirroring and storage-area network (SAN) multipathing/load balancing to server virtualization, adding features such as shared VM boot images with which Symantec hopes to lure VMware customers that are not satisfied with the storage capabilities of the leading server virtualization platform. 

Soderbery says that VxVI will work well with Microsoft’s forthcoming Xen-inspired hypervisor, Hyper-V. “Microsoft has done something pretty interesting here in being open to the Xen community and encouraging the Xen community to be open with Microsoft,” says Soderbery. “Veritas Virtual Infrastructure is technology that we can apply across the Xen ecosystem and Hyper-V as well.”

With another Xen-based virtualization product on the market engineered to be more compatible with the forthcoming Hyper-V, VMware may feel the pinch as users see more options with the other big players in the server virtualization market. But will the $4,595 per two-socket server for Veritas discourage VMware users from even running a demo?

What do you think? If you plan on deploying Veritas VxVI, we want to hear from you. Send us your thoughts via email.

Hyper-V could benefit from VMware’s Xen-based competition

If Hyper-V doesn’t convert the VMware faithful as soon as Microsoft makes its hypervisor generally available later this year, it may get a little help from its friends: Xen-based virtualization platforms.

Some like IT consultant Ardalan Dlawar believe that Microsoft will leverage support for Xen-based platforms to increase competition with VMware. “And Xen will have more third-party support and fewer compatibility issues,” according to Dlawar.

Despite user arguments that ;Hyper-V will have to deliver more than a lower price tag to win users, Hyper-V will certainly get consideration from many VMware customers. While organizations want to maximize their VMware investment, especially enterprise customers which deploy tens or hundreds of VMware virtual machines, Hyper-V evals will most likely be deployed, according to Andi Mann, the research director at Boulder, Colo.-based Enterprise Management Associates (EMA).

Based on a survey of more than 600 enterprises, EMA found about 30% of enterprises have already planned a Hyper-V deployment even with Hyper-V’s general availability several months away. In addition, Microsoft is actually within 10% of VMware in current and planned enterprise deployments according to EMA’s data. Also consider this EMA finding: Xen-based platforms already account for more than 40% of current or planned deployments, the data suggests that the market demand for VMware alternatives won’t disappear.

“VMware is still way out in front in server virtualization,” said Mann, “but both Microsoft and Citrix Systems are definitely catching up.”

Of course, VMware and Microsoft aren’t the only options available. As managers continue utilizing toolsets available from Xen-based products such as Citrix’s XenServer and Virtual Iron Software, VMware and Microsoft are both working on tool sets that enable users manage their virtualization counterparts respectively.

“Both VMware and Microsoft understand that they are not going to be the only players on the market, they recognize that customers are leveraging their competitors’ technology in different parts of their businesses,” according to Adnan Hindi, the VP of operations at ScienceLogic in Reston, Va. Hindi said that companies like his, which produces cross-platform appliances, will benefit from multiple-platform virtual landscapes. As shops continue to see benefit in the utilities that Xen-based products offer, Hindi sees a universal virtualization tool set ultimately working itself out; these tools would essentially equalize platforms in the market and dilute decision making in choosing a virtualization platform largely down to cost.

Over the past year, there’s been a lot of talk about VMware’s cost of VMware. But the price of VMware Server is right for small businesses, said Brett Riale, an IT consultant in Pittsburgh, who feels “truly blessed that programs as functional as VMware Server have been released for free.” Riale is hesitant to trust another Microsoft virtualization product after “the debacle” that was Virtual Server 2005. “Unless it absolutely outperforms VMware,” Riale said that he won’t consider Hyper-V in the near future. And Dave Baughman, a systems administrator for Muncie, Ind.-based Ontario Systems, thinks that his ESX system is “a consistent platform” and that the price of support is worth their investment. “Most of the cost is for support and (VMware’s) support is very good,” says Baugham.

But what will happen when all the Microsoft customers with enterprise agreements get a taste of Hyper-V support? Or if Microsoft offers more third-party support for Xen?

Howard Holton, a system engineer, said that market share will shift in Hyper-V’s favor.

“Hyper-V is an excellent solution for many of those that cannot afford the steep cost that ESX server requires,” says Holton, who has already has a positive experience working with the release candidate and points out that for most data center operations, VMotion’s High Availability (HA) is overkill. ”Hyper-V fits into the market below VMware for hosts that do not need true HA.” 

Holton said that in the long run Hyper-V might win out over VMware because Citrix’s XenServer has finally given Xen a roadmap. XenServer is the spoiler, with a lower TCO than VMware. Although price hasn’t deterred Holton from delivering VMware to his customers in the past, he predicted that Hyper-V will only increase in value.

“As a value-added reseller in the small to midsized space, VMware is the leading virtualization product that I offer. That is changing.”

Virtualization performance benchmarks needed ASAP, vendors say

Big players in the virtualization world griped about the absence of performance benchmarks for virtual machines on CIO Talk Radio yesterday and discussed some of the issues surrounding virtualization standards.

Guests on the show included: Simon Crosby, Chief Technology Officer of the Virtualization and Management Division of Citrix; Tom Bishop, Chief Technology Officer, of BMC Software; Dr. Tim Marsland, Sun Fellow, Chief Technology Officer, for the Software Organization at Sun Microsystems Inc.; and Brian Stevens, Chief Technology Officer and Vice President of Engineering at Red Hat.

The glaring ommission in this lineup: VMware, Inc.

The panelists on CIO Talk Radio didn’t mention VMware by name, but did complain that some companies aren’t being open with their performance data, thus prohibiting the virtualization industry from publishing comparative performance data.

VMware’s licensing agreement for ESX allows users to conduct internal performance testing and benchmarking studies, and allows those users (and not unauthorized third parties) to publish or publicly disseminate the data provided that VMware has reviewed and approved of the methodology, assumptions and other parameters of the study.

Users that have published benchmark data, like Sr. Systems Engineer Mark Foster did on his blog, have had to unpublish results because of VMware’s stipulations.

VMware introduced its own free benchmarking tool, VMmark, last year for certain applications.

Meanwhile, the SPEC Virtualization Committee has been working to create standard benchmarks for VMs. The committee’s goals are to deliver a benchmark that will model server consolidation of commonly virtualized systems such as application servers, web servers and file servers; provide a means to compare server performance while running a number of VMs; and produce a benchmark designed to scale across a wide range of systems.

SPEC expects these benchmarks to be available by the end of this year, but the timeline is not set in stone, according to the website.

Sun’s Marsland said benchmarking progress has been slow because there isn’t an easy way to define a workload, and a large number of benchmarks are required.

“We are talking about a virtual computer, with lots of aspects that need to be benchmarked,” Marsland said. “Every component that gets virtualized needs to be benchmarked.”

Having an open, standardized way of benchmarking is expected to push virtualization further into the mainstream because it will eliminate false perceptions about performance, panelists said. For instance, “there is the thought that I/O intensive workloads can not be virtualized, and the absence of benchmarks prevents us from proving otherwise. It is important for us to have good benchmarks out there,” one panelist on the show said.

Though users look at benchmarks, this type of data is most useful to vendors and OEMs who can use the performance standards to improve the technology, and of course, market their products.

“More open scrutiny of performance results will help us to improve as an industry overall,” Bishop said. “There are ways to measure performance in non-virtual environments, and people are adapting those techniques to get the most out of their virtualized environments.”

In terms of application performance in virtual environments, the issues differ depending on the data center infrastructure. The network, the servers and the storage all affect performance, said Stevens of RedHat.

“The areas that have to progress are around I/O. Intel and AMD are improving around page tables, and we will see improvements around I/O adapters soon,” Stevens said.

Another problem with virtualization? There are support challenges. If an application running in a VM starts acting wacky, the application vendor may not support it, Crosby said.

Licensing and support in virtual environments has been a major gripe with Oracle, for example, which does not support running its applications with VMware.

“It is a reasonable concern…right now there is irrational market based control. Some folks are abstaining from supporting certain apps [in virtual envionments]. As customers demand support, things will hopefully get rational, by next year I hope,” Crosby said.

Xen: An endangered species in the virtualization ecosystem?

While Citrix Systems’ Xen’s ubiquity may help the technology earn a legacy as the invisible hypervisor, it may also prove the most challenging next step for IT administrators and developers who want to find or develop software that leverages, supports or extends the Xen hypervisor.

To understand the problem that Xen faces, take Java as an example. Java is great, and I am committed to developing applications that are truly cross-platform using what I consider this fantastic creation. But in all the years that Java has been around, it has failed to gain traction that NET has achieved in less time. Why?

Although Java is slower, it offers a greater advantage than .NET in terms of portability; but Java still hasn’t managed to gain a majority mindshare of developers. This is because Java’s true worth is its portability, its ability to blend into any system. Java has succeeded so well at being invisible that it has lost the sexiness associated with languages used to construct desktop and Web applications. Every once in a while, something like the Google Web Toolkit comes along that makes people take a step back and re-evaluate Java’s usefulness for end-user applications. Ultimately, Java has been left to the obscurity of providing enterprise, back-end applications.

Is Xen is destined to a Java-like fate? While ultimately it may not prove difficult to develop cutting-edge technology compatible with the Xen hypervisor, it may prove so to market it. If you are in the business of selling virtualization add-on products, you want to ensure that your product is compatible with VMware Infrastructure, because that is where the sales are.

The marketplace has not been especially kind to Xen for two reasons: it was not first to market, which is an important factor for any industry, and Xen resellers do not have the power of the VMware PR machine. Also, all major virtualization vendors, including VMware, say that hypervisors should be ubiquitous — the difference is that the VMware CEO Diane Greene has been quoted on virtualizationreview.com and in person. VMware shouts the same thing everyone else is casually discussing and this makes headlines.

As Xen’s legacy may be to become the ubiquitous, embedded hypervisor for all to use, its strength may also be its greatest detriment to Xen-based virtualization platforms. Xen’s strength is its practical application as the invisible, reused, resold, embedded hypervisor, but invisibility just hasn’t worked in Citrix’s favor. Instead, it shields partners from building ecosystems around Xen and has marginalized the brand name.