This article can also be found in the Premium Editorial Download "Storage magazine: Should you consolidate your direct-attached storage (DAS)?."
Download it now to read this article plus other related content.
Has the storage consolidation parade rolled through your town yet? Storage vendors are in the front of the line, mustering a crowd with promises of a fast ROI, reduced TCO, simplified management and streamlined backup and recovery. Their pitch is downright seductive: Consolidate your direct-attached storage (DAS) into a giant, single logical pool of storage and then allocate and reallocate this capacity as needed with just a click of a mouse. It's a compelling pitch. And the promises are true, except for one thing--none of it is easy, fast or cheap.
"It is getting easier, but there are still obstacles," says Scott Robinson, CTO, Datalink Corp., Chanhassen, MN, a storage consulting firm. And the hard-dollar savings don't come right away. To the contrary, it will likely cost much more at the outset: "You'll be buying a lot of new hardware and you have the whole cost of buying a network," he says. Still, the payoff from consolidation can be big if you carefully and patiently work through the obstacles.
For example, most consolidation involves Fibre Channel (FC) storage area networks (SANs), which still present significant technical hurdles for most corporate IT departments. "We have a lot of technical skill here, but the change to Fibre Channel was difficult, much more difficult than, say, trying to make SCSI work on a PC in the early days of SCSI," says Kelly Carpenter, senior technical manager, Genome Sequencing Center, Washington University School of Medicine,
The Center's IT group called Datalink for help when it tried to consolidate 15TB of varied storage onto a large Hitachi storage system. "Fibre Channel is very finicky. You have to have the right versions of the drivers matched with the right firmware. You need somebody who really knows what works with what," Carpenter says.
No quick payback
Carpenter's experience seems easy compared to what others have encountered. In interviews with storage managers in the midst of consolidation efforts--managers who have requested they and their organizations not be identified--the widespread consensus is that storage consolidation is harder, costs more and takes longer than expected. "If you think you are going to consolidate and get a fast payback, you are living in a dream world," says a storage manager at a large bank. To begin with, that giant logical pool of storage is extremely difficult to set up correctly. "It is very hard to get the zoning and the LUNs right," he says.
Consolidating tape backup when you consolidate storage increases your payback. Storage consolidation streamlines the tape backup process in the following ways:
In his experience, you can consolidate to a point. "You can go to about 40 servers and their attached storage," he says. More than that and the multiple operating systems, different release levels, varied firmware and devices from multiple vendors will turn into an implementation and management nightmare. "Just mapping which application on which server goes to which individual LUN can drive you crazy," the bank's storage manager says.
The bigger problem, adds a storage manager at a leading insurance company, "is that consolidation is really about changing the way we do business in IT." Previously, the standard IT approach to solving a problem was to throw more hardware and infrastructure at it. "With consolidation, we are now scaling back this infrastructure and that means scaling back the operational processes that run the infrastructure if you hope to get any of the benefits from consolidation," he says.
Business unit buy-in is key
Not only will people in IT resist, but the business units will scream about these kinds of operational changes. "The business units want to control their own destiny," the manager from the insurance company says. To them, it means having their own applications running on their servers and storage. Even guaranteeing dedicated LUNs within a consolidated storage infrastructure won't satisfy them unless you can deliver the whole benefits package immediately--better performance and availability and lower costs. And if business units with different service level requirements have to share key portions of the storage infrastructure, you not only face an extreme technical balancing act, but a diplomatic challenge as well.
Despite the difficulties, the researchers and analysts remain bullish about the opportunities in storage consolidation. "Our research confirms that storage consolidation provides real operational benefits and delivers real savings," says John McArthur, VP of storage research, IDC, in a report for Hitachi Data Systems (HDS).
For instance, "The cost of managing information is sharply reduced when storage is consolidated and centrally managed. Labor costs are the biggest factor. As a rule of thumb, half of the staff can manage twice the data in a state-of-the-art data center," McArthur says. In addition, the need to maintain fewer facilities coupled with tighter control over storage assets produce more savings. Even more gains follow through integration. "Once consolidated, the integration among storage systems can be improved," he says.
Enterprise Storage Group's senior analyst, Nancy Marrone, cites similar benefits from storage consolidation. However, she's quick to point out issues that must be addressed before organizations can effectively consolidate their storage. These issues involve sizing, resource management and the degree of heterogeneity in the storage to be consolidated.
"You have to appropriately size your consolidation," says Marrone. A large amount of the direct-attached storage, for example, goes unused. Just counting existing storage won't give you a correct figure.
Similarly, you need to do some serious storage resource management before you consolidate by reviewing what you are actually storing. "You need to look at the files and ask how much of that data you really want to consolidate," Marrone says. Some of that data probably should be shipped off to archival storage. Other data most likely should be thrown away.
Finally, she warns IT managers about consolidating storage from different operating systems. "You have to be careful about how you zone off Windows or it will grab every available LUN," she says.
There's also the question of what to do with the existing storage arrays. When you are consolidating on a SAN, some arrays could be retrofitted for FC. This may be appealing in tight economic times when the folks in accounting pressure IT to squeeze every bit of depreciable life out of each storage asset. "In theory, you can attach the existing devices to the SAN, but usually companies want to upgrade the disk at the same time," says Datalink's Robinson. Often the older devices carry higher maintenance and support costs compared to newer devices, so hanging onto them is no bargain.
To ease the strain on its budget when it consolidated storage, the Los Angeles Unified School District used a lease-to-purchase strategy, says Greg Rapozo, deputy director of data processing for the school district. The project entailed consolidating DAS on a SAN using IBM's Enterprise Storage Server 2105 with Brocade switches connecting to the school district's Parallel Sysplex and Unix systems. The resulting system more than quadrupled the total disk capacity to 3.5TB, increased disk operation performance by 60% and reduced backup time by more than 80% without stressing the budget.
This was first published in June 2003