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Better disaster recovery
Of Oak Hill's 16 physical VMware hosts, all but three are connected to the SAN, a decision which has greatly improved Oak Associates' disaster recovery capabilities, Hill says. Its SAN array, an EMC Symmetrix 8830, houses the VM images, and is mirrored to a remote disaster recovery site using Symmetrix Remote Data Facility (SRDF). Because they boot over the SAN, "when we go into DR mode," Hill explains, "all we do is attach to those [virtual] disks and away we go."
The VMware/SAN combo has also allowed Oak
Associates to recoup some of the hardware costs of implementing DR. "Before VMware, we used to have identical hardware at the remote site," Hill says. But now that a server is "just a file" that can run on any Intel hardware, Oak Hill was able to recycle its old Compaq servers for use at the disaster recovery site.
In a similar vein, running applications within virtual machines is allowing Esmond Kane, a systems administrator at an Ivy League university, to run Apache Tomcat, a free public-domain Java applet server "that falls down a lot." When the application fails, Kane simply starts up another virtual machine instance preconfigured for Apache, without having to reboot the entire system. He is running a VMware GSX Server on local disk, and is evaluating EMC Clariion disk arrays.
The combination of virtual machine software--in addition to a SAN--can also dramatically reduce the amount of time it takes to do day-to-day server provisioning. Michael Thomas, a lead infrastructure architect for a federal agency, is another VMware ESX Server customer running it on a mix of approximately 80 one- and two-way IBM and HP blades. Thomas is serving up many different applications: infrastructure applications such as domain controllers and DHCP servers, as well as SQL Server and application servers.
Thomas' blades are connected to arrays from a variety of SAN vendors--EMC, HP, Hitachi Data Systems Inc. (HDS) and Snap Appliance's new Snap Server 15000. Cristie Data Products' Cristie Bare Machine Recovery is used to provision a new server and assign virtual machines. Adding a new virtual machine "is all scripted, and with Cristie, it's pretty easy at this point," Thomas reports. The amount of time it takes to provision a new server "depends on the amount of data loaded," but Thomas puts the worst case at well under an hour.
This was first published in July 2004