Solaris Containers is an example of operating system virtualization, in which a single operating system is partitioned into several soft partitions. Other examples of operating system virtualization include SWsoft Virtuozzo and its open source counterpart OpenVZ.Containers keeps Web, ERP upgrades on track
For Kichler Lighting, Containers has enabled IT to make upgrades without having to shed its Unix platform simultaneously. About two years ago, Kichler Lighting embarked on its tri-annual hardware refresh cycle, said Mike Sink, director of IT infrastructure at the Cleveland-based decorative lighting manufacturer, and considered whether it made sense to keep its BEA Systems WebLogic Server and PeopleSoft applications on Solaris or whether to move to IBM AIX or another platform. But the firm was reluctant to move away from the tried-and-true Unix platform.
For one thing, Kichler was also in the middle of a storage virtualization project in which it hosted IBM and EMC disks behind IBM System Storage SAN Volume Controller (SVC). Undertaking a concurrent switch to IBM AIX "would have required retraining our staff; it would have been too much," Sink said.
So Kichler found another option. Thanks to a backward compatibility feature in Solaris 10, he discovered that Kichler could still run legacy versions of its BEA and PeopleSoft applications in a container while the IT department tested newer versions. "The business really wants to get to the latest version of PeopleSoft, and Containers give us a lot of flexibility to create dev and test environments that we'll use for now, then throw away," Sink said.
Kichler went ahead and purchased fewer, more robust systems, consolidating upward of 40 systems onto 10. Currently, Kichler has about 85 applications running in Containers, a number that's growing daily, Sink said. Previously, systems would run clustered at about 15% utilization, Sink reported; today, Kichler's clustered 12-way Sun Fire E2900 servers run at about 65% to 70% utilization, he said, fully loaded with 96 GB of main memory.
Storing applications in a container has also given Kichler better availability, Sink reported. Back in the days of one application to one server, it would take Kichler about four hours to recover from a system crash; it had to restore the entire system. With the app running in a container, a restoration takes about 15 minutes, including the time it takes to retrieve application data off of tape, Sink said.
Compared with the more pervasive host-based virtualization platforms such as VMware Inc.'s ESX Server and Xen, applications running on Containers must all be on the same operating system and patch level. This limitation aside, operating system virtualization is known to deliver low overhead and good performance.
But last month, Sun announced Solaris Containers for Linux, previously known as BrandZ, which may minimize some of the inflexibility of Containers. With it, Sun Solaris users will be able to run unmodified Red Hat and CentOS Linux applications in a Container without having to recompile.
Save a few Linux-based hardware appliances, Kichler doesn't run much Linux in its shop, so it probably would not have use for the new capability. But its availability may make Solaris Containers an interesting alternative to VMware-style virtualization for large Sun shops looking to consolidate their systems.
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