In a cutthroat industry where there is little to agree on, execs from top storage vendors had no problem finding common ground on an aspect of Microsoft’s System Center Virtual Machine Manager (SCVMM).
It turns out that when an administrator connects an ISO (slang for a CD or DVD image file) to a virtual machine, SCVMM deploys a copy of the file to the virtual machine’s directory. Templates made from such a virtual machine also retain their own independent copy of the image file. SCVMM even extends the favor to managed VMware environments by making a copy via SFTP to an ESX host.
Unknowing administrators accustomed to the single shared image approach employed by VMware VirtualCenter may be in for a surprise when gigabytes of expensive SAN storage suddenly start to disappear.
In a recent (made-up) summit on ISO image file deployment best practices, top industry thinkers weighed in:
“If there is one thing we can agree on,” said one source insisting on anonymity, “we really prefer SCVMM’s handling of ISO images over VirtualCenter. We also obviously prefer one VM per LUN and substantial overallocation for snapshots and future growth.”
“Absolutely,” agreed another. “We wholeheartedly embrace the concept of copying the two to four gigabyte DVD images from one central repository to the SAN whenever possible. And please, do not go back and remove the image files after using. They may be needed again someday.”
One storage analyst wrote in a whitepaper curiously sponsored by three top storage vendors:
While VMware’s VirtualCenter may allow administrators to connect multiple virtual machines to a single, shared instance of an image on the SAN or on an inexpensive NFS share, we do not encourage that design. We have found that practice to seriously impact storage shipments and next quarter’s numbers the overall satisfaction of our customer virtualization SAN deployments.
It is not at all clear why VMware chose to take this minimalist approach. After all, the improved manageability of replicating identical ISO images throughout hundreds of virtual machines and templates is much more analogous to non-virtualized storage and physical CD-ROMs. Isn’t the leading virtualization company concerned about providing their customers an equivalent experience?
Are you pro- or anti-ISO proliferation? Did you have a choice?
Folks, this article is satire. Lighten up.