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Demartek Asks: Matching the Physical and Logical Topologies - How Important Is This?

12 June 2009

On June 11th 2009, the Wikibon community gathered for a Peer Incite Research Meeting with Burzin Engineer, Shopzilla’s Vice President of Infrastructure Services. Shopzilla, an online shopping comparison service, faced huge data growth and ever-increasing power consumption in its IT operation. To help solve these challenges, it implemented an in-line NAS storage compression solution from Storwize.

Not surprisingly, when implementing a new solution into an existing environment, Shopzilla faced some interesting and non-trivial technology integration issues. It spent significant time planning for the installation of this in-line storage compression solution, making sure the system was deployed in the correct place in the storage topology to insure minimal downtime. The plan was to deploy this solution first in the test and development environment, then to the production environment.

Because this is an in-line solution, Shopzilla had to disconnect its NAS devices temporarily to insert the redundant storage compression appliances into the network. Although good planning showed the logical position in the network where these appliances should be installed, Shopzilla found that in actually implementing the physical connections, it had missed a few items. It found that over time, as in most networks, small physical network connection adjustments had been made for various small projects, upgrades, etc., creating some unforeseen “disconnects.”

To solve this challenge, Shopzilla had to examine all of its physical network connections, including every cable, port and connector in the path between the servers, switches and NAS devices, carefully. By becoming re-acquainted with its physical network connections and matching the logical network topology with the physical connections as it existed, Shopzilla was able not only to complete the installation of the Storwize in-line NAS storage compression appliances, but also develop a current and accurate network topology layout that could be used for other projects.

Action Item: IT shops need to understand not only the logical configuration of networks, but also the physical configuration and insure that these match. This applies to both LANs and SANs. A periodic check that the logical and physical topology information match and are correct is an important task, and no change, however small, should go undocumented.

This article is also posted on the Wikibon Professional Alert page.