The University of New Mexico Hospital began trying last summer to migrate some 3.5 terabytes (TB) of data off of...
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a five-year-old Xiotech Corp. Magnitude Classic array and onto the EMC Clariion CX500, which holds the rest of its administrative data. The hospital, a Dell Inc./ EMC shop with 100 TB of storage, enlisted Dell services engineers to perform the migration, and not surprisingly, the first product those engineers brought in was EMC's SANCopy software.
"We knew within a matter of hours, definitely less than a business day," that it wasn't going to work," said Mike Biedermann, systems analyst with the University of New Mexico Hospital. Biedermann said the SANCopy software, which was installed on the CX500, couldn't see the LUNs on the Xiotech array it was trying to pull the data from.
"It could see the device as a whole," Biedermann recalled. "But it couldn't recognize the LUNs within it."
Back to the drawing board -- a few months later, Dell engineers brought in colleagues from Brocade along with Brocade's Data Migration Manager (DMM) product, an appliance that sits between two devices in the fabric to perform migrations.
The hospital's production fabric is entirely composed of McData Corp. products; the Brocade engineers brought in their own switches, as well as the DMM appliance, and created a separate fabric for the migration. "They wanted to make sure, since the migration had already been tricky, that the appliance was working with switches they knew it wouldn't have any issues with," Biedermann said, who assisted the engineers in setting up the migration fabric.
Finally, in the course of less than 24 hours beginning on Oct. 20, the migration was successful, in less than half the allotted time for the job. Mario Blandini, director of product marketing at Brocade said the DMM's central position in the fabric and the fact that its migration capabilities are hardware-based were what led to the shorter migration window. The separate fabric, based on Brocade AP7420 switches as well as the DMM appliance, was removed afterward by the Brocade and Dell engineers.
"In a similar situation, it's something I'd definitely consider using again," Biedermann said of the DMM. But, he added, he wasn't interested in purchasing the device. "I'm not sure what the day-to-day value-add would be."
It's a comment that echoes a previous beneficiary of the DMM in a services capacity, Randy Simons, director of network operations for the Rancho Santiago Community College District in Orange Country, Calif. The DMM tool, which costs $85,000, is a "one-time use" product, Simons told SearchStorage.com. "If you want to move massive amounts of data in a short amount of time, it's definitely the way to go." Simons said Hewlett-Packard Co. (HP) should license the tool and use it as part of a service; word has it HP has since been "unofficially" licensing the DMM product to perform migrations for customers.
Hardware vs. software for migrations
Brocade's engineer on the project, professional services consultant Vernon Rubenic, said he wasn't sure why the Brocade product was successful where SANCopy wasn't, but that the migration project hadn't involved any extra scripting or finagling of the DMM beyond normal configuration procedures.
"Brocade has tested the platform to work with the Xiotech Magnitude Classic," noted Blandini. "It just may not be supported by the EMC product."
EMC's director of public relations, Michael Gallant, confirmed that Xiotech's products are not qualified with EMC through its e-Lab program, but said that EMC has a host-based migration product, called Open Migrator. The product was released in August 2005, but according to Dell spokesperson David Graves, is not offered by Dell.
Graves also said that the product at the time did not support boot-from-SAN infrastructures, or the Novell operating system, both of which the University of New Mexico Hospital has in use.
Meanwhile, Brocade claims in general that its product works faster than most software-based migration products. Simons told SearchStorage that he had originally planned three days to migrate 3 TB of data between EVA SANs, but the project actually took a day and a half; Biedermann said the migration of 3.5 TB between his arrays took around 24 hours.
For his part, Biedermann said that in general, he is not comfortable with host-based migration utilities. "We do not feel as comfortable using a host-based migration utility, as we have had previous experiences doing host-based migration when upgrading hardware on non-SAN-attached servers," he said. "We found there was significant data loss doing this kind of data transfer."
"This case highlights that solving migration issues at different levels of the infrastructure can create different advantages and disadvantages," said Brad O'Neill, senior analyst with the Taneja Group. "If you have a lot of data to move and an established backend, array-to-array migration tools are really attractive to a lot of people because they tend to be faster -- whereas if you have a smaller, more dynamic workload, you tend to have more success doing a host-based process."
However, O'Neill pointed out, the fabric-based approach can also add complexity, "as in this case where they had to build out a separate fabric. It all depends on the skill sets of your IT staff and what you're most comfortable with."
Finally, why didn't the Dell engineers try EMC's Invista virtualization switch for an EMC customer's migration? According to Gallant, "Dell does not resell Invista, and it's not suitable for use with this kind of migration -- EMC probably wouldn't have considered it, either, even if we were the direct rep on the account." Gallant said the Invista would be too high end an item to bring in for one migration in a case like this.