The new Citrix XenServer 5.5, which was announced today, includes several new features, but none as big as role-based...
access control via new Active Directory (AD) integration, said users and experts.
Bill Kleyman, the director of IT at Worldwide Fittings Inc., says 5.5's AD integration is "an infinite step over what they have now, which is nothing." Currently, to manage XenServer, administrators must log in as root "or do crazy backflips with Linux," Kleyman said. He oversees three XenServer hosts running about 15 virtual machines and will upgrade to 5.5 as soon as it is available, he said.
For many shops, a lack of role-based access control has been a deal killer, said Shannon Snowden, a consulting partner at New Age Technologies in Louisville, Ky., a professional services firm and Citrix and VMware partner. Now Citrix has "addressed the single biggest hurdle to enterprise adoption," he said. Role-based access control "will help equalize some of the final decision criteria."
That's a good thing, because certain workloads perform better with XenServer than with VMware ESX, Citrix's principal competition, Snowden said. "Different workloads perform differently on different platforms," Snowden said, who recently oversaw the deployment of XenServer to virtualize XenApp (or Presentation Server) in a "heavily penetrated VMware shop," he said.
Another feature of the free XenServer 5.5 is support for SUSE Linux Enterprise Server (SLES) 11, Debian 5.0 and RedHat/CentOS/Oracle 5.3 running as guests. Also, the new XenConvert supports virtual-to-virtual migration from VMware's Virtual Machine Disk Format to the Virtual Hard Disk (VHD) format used by Citrix and Microsoft, plus support for the Open Virtualization Format, Open Virtual Appliance and XenServer Virtual Appliance formats.
Deeper storage integration to broaden XenServer adoption?
Citrix also announced version 5.5 of its add-on management pack Essentials for XenServer and Hyper-V. Highlights of the release are the previously announced automated lab management and dynamic workload balancing, and improved integration with third-party storage.
Third-party storage integration, which could drive wider adoption of XenServer, occurs via Citrix's StorageLink technology, a set of application programming interfaces that allows XenServer to take advantage of native features of the underlying storage array. Such features include snapshotting, deduplication and thin provisioning. With this release, the number of partners that have integrated or committed to StorageLink increases to 20.
New disk array manufacturers writing to StorageLink include Compellent, Hewlett-Packard Co., LSI Corp., Pillar Data Systems, Reldata Inc. and Xiotech Corp., in addition to existing partners NetApp and Dell EqualLogic. Citrix has also lured SAN networking equipment makers (QLogic Corp., Brocade Communications Systems, Emulex Corp.), and storage software providers (CA, CommVault, DataCore Software Corp., FalconStor Software, PHD Virtual Technologies, SteelEye Technology and Vizioncore Ltd.) into the StorageLink fold. One notable absence on the list is EMC Corp., VMware's parent company.
Broader storage array support is a good thing, but StorageLink's real coup will be to improve XenServer's backup story, said Chris Wolf, an analyst at the Burton Group. Most backup software providers already support VMware; next on their list is Microsoft Hyper-V, and "Citrix after that," Wolf said. But because Essentials works with both XenServer and Hyper-V, "this allows Citrix to ride on Microsoft's coattails and get supported a lot faster."
Speaking of backup, XenServer 5.5 also touts a new Consolidated Backup feature, which allows third-party software providers to interface directly with XenServer and provide full and incremental, in-guest, file- and image-level backups of virtual machines, the company reported. It also allows administrators to schedule backups and snapshots directly from XenCenter, XenServer's management console. At the same time, New Age Technologies' Snowden cited XenServer 5.5's new support for the Logical Volume Manager, which he said will make it easier for administrators to work with VHD files, regardless of whether they use NAS or SAN-based storage.
What's still missing
Despite all the new features, XenServer 5.5 still has obvious shortcomings relative to the VMware's recent release, vSphere 4. One is the lack of a distributed virtual switch, which simplifies virtual switch management for VMware administrators, said Burton Group's Wolf.
Not to be outdone, Citrix told analysts that it intends to do something similar with the next version of XenServer, except rather than create a proprietary product, it will develop it as open source, said.
The baseline XenServer 5.5 also doesn't include memory overcommit, or ballooning as it is sometimes known. Memory overcommit gives VMware ESX a substantial leg up over XenServer, Wolf said, "because of the density benefits it gives you are substantial."
Citrix is aware of that problem, though, and is working on it for its next major release, Wolf said.
But that doesn't detract from the fundamental soundness of the release, Wolf said. This winter, the Burton Group issued a report evaluating the different hypervisor platforms. At the time, "VMware was the only platform we would recommend for enterprise use," Wolf said. That's about to change. When XenServer 5.5 ships, "it will be a production-ready platform."
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