Linux can match and outshine Windows in data center — thanks to its strong security, reliability, and long term usability — but it has upsides and downsides on the virtualization side, according to software engineer and Linux and VMware Server technologist Chris Berg. In this excerpt of our Q&A, Berg gives a power-user’s view of Linux’s strengths and weaknesses on the virtualization front.
“By providing a solid, low or no-cost platform out of the box, strong virtualization solutions abound on Linux,” Berg said. “Solutions such as Xen or VMWare ESX server put Linux on even ground…by offering a comprehensive virtualization solutions and easy to use interface.”
My interview with Berg is an offshoot of coverage of the recent LinuxWorld/Next Generation Data Center Conference. Getting connected with veteran users is the best thing about covering these shows, I think. So, here’s what Berg had to say.
In what ways will virtualization spur wider adoption of Linux on the server side?
Berg: A variety of both open and proprietary solutions are available for Linux including KVM, Xen, VMWare ESX Server. The cost of these solutions ranges from nothing up to tens of thousands of dollars. The benefit to a wide variety of virtualization solutions is that an organization is free to choose a solution that fits their needs. The variety of choices and costs is what will spur the adoption of Linux on the server side.
Whereas some Linux virtualization solutions are not “bare metal”, installed on an existing Linux server products, others such as VMWare ESX server consist of a fully-installed Linux distribution under the hood. This enables the ESX server to be maintained like an appliance, with little operating system level interaction.
In what ways will virtualization make no difference in adoption of Linux on servers?
Berg: The current virtualization trend does not translate to across the board adoption of Linux. In cases where a virtualization solution isn’t “bare metal,” there won’t be as large a push for Linux due to internal support staff’s familiarity with Windows servers. Due to the variety of solutions available for virtualization on Linux, there can be a variety of interfaces to maintaining an installed solution. This can be daunting for IT support staff and those seeking third-party technical support.
What technology or market trends will help increase Linux server adoption in the enterprise in the rest of 2007 and early 2008?
Berg: As the virtualization push continues, Linux server adoption in the enterprise will continue to increase. Either through a solution that relies on an installed Linux or a solution like VMWare ESX Server that uses Linux under the hood.
The continued push for higher value offerings will see Linux continue to be deployed in essential services roles, such as providing DNS, DHCP, proxy services and continuing into the application server space as many independent software vendors continue to invest in Open Source.
In general, what barriers stand in the way of adoption?
Berg: One of the largest barriers to Linux server adoption in the enterprise is the back room nature of Linux success stories. In many large enterprises Linux is deployed on the server and performs capably, but the word never gets out.
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VMware finally staged its initial public offering (IPO) today, with EMC selling 10% of its stake in the company, or 33 million shares, and raising almost a $1 billion in the process. The shares were priced at $29 – higher than expected just last week – but by midday had shot up to over $50 per share.
To anyone who’s watched the company over the past couple of years, that the VMware IPO was a rollicking success should come as no surprise. Quarter upon quarter of consecutive growth. Tremendous goodwill from its partners and customers. A slew of imitators and competitors. A healthy ecosystem or start-ups hoping to capitalize on its success. Even entire websites devoted to the core VMware technology
More interesting, I think, is how VMware’s newfound semi-autonomous status will impact it product development, and more importantly, how the company deals with its customers?
Public companies are different from private companies, which are different from wholly owned-subsidiaries (even independently operated ones). Sure, right now, VMware can do no wrong, but how will having Wall Street breathing down its neck every quarter impact the company’s ability to create important and fully baked software? How will the emphasis on quarterly results influence the VMware sales force, and the way it treats its accounts? Will VMware’s status as a publicly traded company affect its relationships with its partners?
I don’t know the answers to these questions, but will be looking out for clues over the coming months. In the meantime, if you have any theories, feel free to leave a comment, or shoot me an email.
Check out the Enterprise Linux Log for news about Asigra’s new 64-bit agentless backup for virtual servers.
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Virtual Iron's Mike Grandinetti provides insights about the synergies between virtualization, blades, server consolidation and iSCSI in this interview with Jan Stafford, SearchServerVirtualization.com's senior site editor.
Bernard Golden discusses some take aways from Tony Iam’s session at the Next Generation Data Center conference in San Francisco.
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In this video, senior site editor Jan Stafford discusses the fact that KVM, Xen and other virtualization platforms are not interoperable, a subject that troubles users and was given short shrift by vendors at LinuxWorld/Next Generation Data Center Conference 2007 sessions.
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Xen expert Bernard Golden sounds off on Microsoft’s presentation at LinuxWorld 2007 and the impact of Novell’s new Linux SUSE and virtualization products. Golden is a systems integrator, SearchServerVirtualization.com expert and author of the upcoming book, “Virtualization for Dummies”.
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XenSource recently announced a partnership with Symantec that paves the way for Veritas Storage Foundation to be embedded in XenEnterprise 4.0, expected to ship Q307. Note that the OEM includes a fully licensed, unrestricted version of Storage Foundation. The majority of enterprises today rely on Veritas backup and storage management tools, so it makes perfect sense that XenSource would partner with Symantec to build out a more robust storage architecture for XenEnterprise virtualization platforms. By embedding Storage Foundation in XenEnterprise, storage resources will be able to be managed transparent to their dependent VMs. So XenEnterprise will support connecting VMs to disparate storage targets (FC, iSCSI, NAS, etc.), multipath, and relocation to storage resources as needed, without impacting VM availability.
If you’re already a Veritas shop, this announcement should come as significant news. As a result of the XenSource – Symantec partnership, organizations using Veritas Storage Foundation will be able to manage XenEnterprise storage resources using their existing management toolsets. Furthermore, the partnership is also going to result in certified NetBackup solutions for XenSource platforms. Many backup vendors are still sorting out their VMware backup solution set, while Symantec is steaming ahead by adding XenSource to its already supported VMware and Microsoft virtualization backup solutions. There’s a big difference between a “we support VMware and Xen backup” marketing check box, and a robust and well documented solution set for virtual machine data protection and recovery. Symantec clearly gets it. For example, NetBackup 6.5 is the first backup platform to support recovering VM images or individual files from a single VMware Consolidated Backup (VCB) job.
The OEM agreement may also impact organizations that are required to certify their storage management solutions with every new version release. By using a single storage management infrastructure for both server and virtualization platforms, re-certification of storage management following virtualization platform updates will be easier than on virtualization platforms using a proprietary storage management architecture.
Storage management, high availability, and backup support have been three key issues that have stalled XenSource’s assault on the enterprise. All three of these issues will be solved in XenEnterprise 4.0 as a result of the XenSource – Symantec partnership. With Storage Foundation embedded in XenEnterprise, organizations that do not run Symantec (Veritas) software will still be able to take advantage of the new storage features and manage them using their XenEnterprise management tools. High availability and dynamic VM failover will be included as well. Inclusion of high availability into their virtualization architecture will place XenSource in the high availability virtualization club that now includes VMware, Microsoft, Virtual Iron, Novell, and Red Hat.
When virtualizing mission critical systems, I have long viewed high availability and certified backup support as requirements, and have recommended that virtualization platforms devoid of these features remain relegated to training, test, and development environments. With the upcoming release of XenEnterprise 4.0, XenSource appears to be on the verge of crossing the chasm to join the enterprise virtualization elites such as VMware.
Senior Analyst, Burton Group
Note: This post also appears on the Burton Group Data Center Strategies blog.
Software engineers Jeremy Fitzhardinge of XenSource Inc. and Avi Kivity of Qumranet Technologies laid out the pros and cons of Xen and KVM in a LinuxWorld 2007 session, titled “Xen and KVM: Separating fact from fiction” just a few minutes ago. Panelists also included moderator Sunil Saxena and Jun Nakajima of Intel Corp., but I’m focusing on Fitzhardinge’s and Kivity’s takes on the facts about both virtualization technologies.
Let’s start with KVM.
“KVM is based on Linux which is the most scalable operating system on the planet. It shows very good scalability in terms of guests. We expect to be able to run very large guests with great scalability soon,” Kivity said.
KVM tries to leverage hardware virtualization and Linux kernel capabilities to the maximum, Kivity said. KVM leverages Linux memory management and I/O capabilities and its scheduler and security model. Real-time scheduling is made possible with KVM. It’s also easy to use existing management tools with KVM.
“There is work being done to get hardware assistance in KVM,” Avity said. In the meantime, KVM requires hardware assistance. Other cons include a lack of flexibility in device assignment and needs work in memory and power management.
Xen, on the other hand, can run only any platform without hardware support. However, without hardware support, performance can suffer, said Fitzhardinge. In most situations, hardware support is available, so this isn’t a big deal. Xen does need to draw from Linux support for power management and platform initialization.
“Xen has minimal support for power management at this point,” Fitzhardinge said.
On the plus side, Xen has great security isolation, is operating system independent and supports multiple hardware platforms. Xen is designed around paravirtualization, which gives it low overhead and good performance, Fitzhardinge said. Also, Xen supports both paravirtualization and hardware-assisted virtualization.
Unfortunately,KVM lacks manageability features that exist in Xen today, platform initialization with Xen is complex and performance on 64-bit processors isn’t great, Fitzhardinge said.
So, overall, scalability in number for guests and VCPUs is good on both Xen and KVM; but KVM supports power management and Xen does not. KVM has broad machine support, but Xen does not. Both have Linux vendor and community support.
Looking ahead, Xen and KVM developers plan to add enhanced backward compatibility and share I/O device support. Interoperability is also a concern that both development groups will work on. On the full virtualization side, machines images installed on one hypervisor will be obtainable on the other, Kivity said. To what extent the hypervisor will present the same hypervisor interface is the question. At the moment the Xen interface is quite different from the KVM interface, said Fitzhardinge. As Xen goes towards more hardware support, there are more possibilities for developing interoperable interfaces.
LinuxWorld vendor news
SWsoft is previewing Virtuozzo 4.0 at LinuxWorld. The new version, slated for release later this year, has a new, customizable interface and includes additional management tools (management tools trend, anyone?).
Virtuozzo 4.0 can perform cross-platform backups (i.e. store a Windows virtual server backup on a Linux server and vice versa). You’ll also see a full SDK for application integration, template improvements, and even tighter integration with Plesk.