Still, the vast majority of VMware administrators opt for lesser degrees of protection for their vCenter instances.For instance, Bob Plankers, a systems administrator at the University of Wisconsin, Madison, does not use clustering to protect vCenter. Instead, "Our protection scheme for VirtualCenter involves replication of the VC database to another host and periodic synchronization of the local files on the VC server to the backup server," he wrote in an email. "If we do have an outage, we fire up the backup VC server, and away we go." Alternately, an increasing number of VMware shops now use VMware's own built-in high-availability software to protect vCenter. By running vCenter in a virtual machine (VM), it can be re-started in case of a node failure with VMware High Availability (HA). While this approach was once frowned upon, it's now supported by VMware . Using VMware HA to protect vCenter has a lot of benefits over using a clustering technology like Microsoft Cluster Services (MSCS)wrote VMware administrator and blogger Jason Boche. For one, "you probably already have a VI cluster in your environment you can leverage. Hit the ground running without spending the time to set up MSCS." For another, "Removing MSCS removes a third-party infrastructure complexity and dependency, which requires an advanced skill set to support." Not surprisingly, vendors like Symantec don't support this approach. "We wouldn't recommend that," said Nadeau. "Because vCenter is such a critical component of your infrastructure, you would want to keep it separate." Also, there's a limit to the availability you get from VMware HA, said Midvale, Utah-based Burton Group analyst Chris Wolf. Ha recognizes only extreme soft failures such as a blue screen or hanged kernel. "Other than that, [VMware] HA doesn't tell you anything." A product like VCS, meanwhile, has visibility into the application layer, and can make "more intelligent decisions" based on application performance and process characteristics, he said. To a large extent, the decision whether to cluster vCenter depends on VMware administrators' background, said Jean Bozman, the research vice president for the enterprise platforms group at IDC. In discussions with attendees at this fall's VMworld, Bozman noted two distinct types of VMware users: "top down, and bottom up," she said. "Top down" users tend to come from an enterprise IT background and have extensive knowledge of Unix and high-availability software. "Bottom up" VMware users, on the other hand, began using VMware a long time ago as an ad hoc solution, trying to maximize the effectiveness of the x86 platform, and may be comfortable with less bulletproof HA solutions. "I'm not saying that one is better than the other -- just that both groups appear to exist." Meanwhile, Burton Group's Wolf hopes Symantec's foray into protecting vCenter presages better things to come.
"The bigger story here is the move away from looking at a VM as a black box and looking inside it," Wolf said.When VMware acquired B-Hive -- whose Conductor application performance-monitoring software it will integrate in to VMware Distribted Resource Scheduler (DRS) -- started down this road. The availability of tools like Symantec VCS, meanwhile, could give enterprise IT users the availability they need to confidently move "tier-one and tier-two" applications off dedicated boxes and into the virtual realm, Wolf said. This year, look for that to happen in earnest, he said, as systems based on Intel's Nehalem and AMD-V chips with Rapid Virtualization Indexing (RVI) begin to ship.