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New Novell SUSE Linux shop surprised by Xen's polish
By Jack Loftus, News Writer
15 Oct 2007 | SearchEnterpriseLinux.com
Last week, Novell Inc. announced that it would allow Open Enterprise Server 2 (OES 2) to run as a paravirtualized Xen guest on top of SUSE Enterprise Linux Server (SLES). Analysts lauded the move for the backward compatibility it provides to existing NetWare customers running or migrating to OES 2.
The Blackfoot, Idaho-based title insurance agent was about to begin testing for a migration from NetWare to SUSE Linux and wanted to use virtualization technology to combat server creep. Executives believed that virtualization would allow First American to reduce a double-digit number of servers to just two boxes.
"We were alarmed with the way server creep was building up in our data center," said Dan McDougall, First American's corporate IT director. "Even with our handful of [NetWare] servers, we were still running out of power and places to plug in. Virtualization was an opportunity to take better advantage of our hardware."
But initially, the NetWare-centric IT staff at First American was wary of Xen and worried about its polish. Kurt Johnston, a network engineer at First American, had previous experience with VMware's ESX Server. He was concerned that Xen – a relative newcomer compared with VMware – would bog down the shop with performance "hiccups."
McDougall shared similar concerns about Xen, which would run his mission-critical NetWare applications and services in a virtual environment.
"From my perspective, a lot of the articles I'd read in the trade rags seemed to feature people who said they were not adopting Xen because of [performance concerns]," McDougall said. "We were the kind of shop that was against do-it-yourself workarounds. We just did not have the resources."
But McDougall did have a 15-year relationship with Novell and an aging Dell-based server architecture running NetWare 6.5. As with many NetWare shops today, completely eliminating that OS wasn't an option. Customized applications needed NetWare to run properly. Thus OES 2's paravirtualization was appealing in spite of concerns about Xen.
"There were no real legitimate alternatives for us," McDougall said. "Red Hat was an option, and going with pure SUSE Linux was an option, but we were always confident with the new services provided by OES 2 and we trusted Novell; we had worked with them for years."
And as luck would have it, First American has been pleased by Xen's progress. Both McDougall and Johnston agreed that while Xen isn't as robust as VMware ESX Server, their familiarity with Novell and the ability to virtualize NetWare on Linux made up the difference in their choice.Xen matures
"I did not have high expectations for Xen," Johnston confessed. "With Xen being as young as it is, I was expecting it to be very difficult to install and configure a new domU onto dom0. The fact is, it was rather simple to install. It was the ease of installation and configuration that surprised me. I was expecting to use quite a bit of [command line interface.]"
That said, Xen's user interface and management was not up to par with VMware, Johnston said, but he never expected it to be. "I am not concerned with getting proper support for Xen, because the support from Novell has always been stellar and all we have plans for visualizing at this time is OES 2. As far as the reliability of Xen; I have not run it long enough to comment," Johnston said.
Gordon Haff, senior analyst, Nashua, N.H.-based Illuminata Inc. said the number of IT shops "pleasantly surprised" by Xen will only increase going forward.
"A lot of energy and resources have been going into polishing up Xen in its various forms and it's been coming along pretty quickly as a result," Haff said. "Certainly compared with a year or 18 months ago, there's a considerable difference in overall robustness and capability."
Haff couldn't point to specific Xen improvements over the past year that have made the difference but said that Xen has made gains through "a generalized squashing of bugs and knocking down of performance issues."
"It's ''time on station,' really'," he said. "Nothing new; it just takes time for products to mature."
For its part, First American is busy with its migration. The firm deployed Open Enterprise Server 2, SUSE Enterprise Linux 10 and virtualized NetWare via Xen in a replica of its production environment for testing purposes. And First American's issues have not affected the deployment roadmap, which, according to McDougall, calls for the migration to be complete by the end of 2007.
"We have not officially rolled out OES 2; we're going to do that service by service and application by application very shortly. We're still awaiting some final code and documentation" from Novell, which is due to arrive in about a week McDougall said.
When the code arrives, First American will move services over from its older Dell servers down to two new boxes running OES 2 and SUSE. Then the migration will continue with domain name server and Dynamic Host Configuration Protocol.
Once deployed, OES 2, Xen and SLES 10 will run on two quad-core Dell boxes with 8 GB of RAM, McDougall said. GroupWise is the final piece of the puzzle; in early 2008, GroupWise will be installed as a clustered application spanning both servers. Rolling it out will take more time because it is mission critical. "GroupWise lags a little because we want to make sure everything is rock-solid," McDougall said.
Xen, meet LUN
With testing all but complete, Johnston said only one issue with Xen remains.
"One thing I'd like to see in Xen is on the paravirtualization side of things. I'd like to be able to somehow mask certain virtual machines and only allow certain LUNs [logical unit numbers] on the SAN [storage area network] to serve and see certain virtual machines, via Xen," Johnston said. "I'd like to be able to build in a limit to the different servers to see only specific LUNs on the SAN."Having the ability to visualize the host bus adapter (HBA) and use Xen to manage virtual Fibre Channel ports would allow LUN masking of these ports and give the ability to grant access to only specified LUNs, he said.
To be fair, this capability is still an issue in VMware environments as well. But a fix is forthcoming, with support for N_Port ID Virtualization (NPIV) slated for VMware ESX 3.5 announced last week.
"We are working on N_Port Virtualization together with Qlogic and Emulex," said Holger Dryoff, vice president of management and marketing at Novell. "This will be available in one of the future service packs of SUSE Linux Enterprise Server 10 and therefore to OES 2 customers as well."
Another feature of OES 2 is Dynamic Storage Technology. The addition uses customer-defined policies to recognize active and stale data and then automatically shifts it to the appropriate storage device as the data's status changes. McDougall said First American hasn't started testing that functionality but could begin later this year or in early 2008.
On a related note, industry experts warn against overeager server consolidation. While virtualization makes server consolidation and the elimination of server sprawl a real possibility for data centers, IT managers should be wary of virtual sprawl as well.
At VMworld in September, panelists indicated that virtual machine sprawl can quickly become an issue because virtual machines are so easily created and moved.
Email Jack Loftus, News Writer, with your questions and comments on Linux and virtual appliances.