When Oracle Corp. announced its Xen-based variant Oracle VM earlier this week, it claimed "three times greater efficiency than current x86-based server virtualization products." Now VMware Inc. is defepnding itself against Oracle's assertion, laying out in depth the optimizations it has poured into ESX Server to make it the superior virtualization platform for running high-performance databases.
In the blog posting "Ten Reasons Why Oracle Databases Run Best on VMware," the VMware performance team discussed some of the characteristics of databases (their large memory requirements, small, frequent I/O transactions, and large numbers of concurrent users) and how ESX is poised to handle those challenges.
Among other characteristics, the authors highlight ESX's high I/O performance, its ability to scale workloads with virtual symmetric multiprocessing, the large amount of memory that can be assigned to a virtual machine (64 GB) and, in the forthcoming ESX 3.5, support for large pages in a CPU's memory management unit.
And the notion that Oracle VM might run optimized Oracle applications more efficiently than a general-purpose hypervisor shouldn't come as a huge surprise. While Oracle hasn't disclosed how it designed its performance tests, it is known that these tests used Oracle Enterprise Linux, the company's Red Hat Enterprise Linux clone that has been "paravirtualized" -- that is, modified so the kernel can talk directly with the hypervisor -- for better performance, running a finely tuned version of Oracle Database.
VMware supports some paravirtualized operating systems through paravirt-ops and the Virtual Machine Interface, although that capability isn't supported yet on its bare-metal ESX platform.The tip of the iceberg
Performance considerations aside, there's a lot more to virtualization than the hypervisor, VMware maintained. "The hypervisor is just one piece of the puzzle," said Parag Patel, VMware vice president of alliances. "VMware is still the only vendor to feature an end-to-end offering," including breadth of platform support [desktop to enterprise], full management capabilities, tools and advanced features like VMware High Availability (HA), VMware Distributed Resource Scheduler, or DRS, among others.
"What customers are really looking for is a finished product," Patel said. "If what we have is a car, what Oracle is offering is a dashboard or a steering wheel."
Chris Wolf, a senior analyst at Midvale, Utah-based Burton Group, concurs that Oracle VM is lacking. "There's no HA, there's no OS vendor support, little ISV [independent software vendor] support, no official hardware support, no backup. . . . [The lack of HA] alone is a deal breaker."
It's still early days for Oracle VM, however, with demand for virtualizing enterprise applications just ramping up, Wolf said. And on the management front at least, there are several efforts afoot to create parity between Xen-based platforms and ESX. Wolf cites standards efforts from the Distributed Management Task Force Inc., such as the Open Virtual Machine Format and its Common Information Model, or CIM, management profiles for virtualization.
"In a couple of years, running multiple different virtualization platforms might not be that big of a deal," Wolf said.
Despite VMware ESX's huge lead, "Oracle is off to a very good start," and a lot of Oracle shops will probably bite on Oracle VM, Wolf said. "Oracle has a lot of clout. If the product is good and less than VMware in cost, then a lot of organizations are going to take a good, hard look at it."
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