4 ingredients of safe storage every manager should know about
- By Alan Radding
- May 22, 2006
For many years, storage technology followed a predictable course — in development and use. Regular upgrades in storage capacities and data transfer speeds were as reliable as the changing of the seasons. Meanwhile, users faithfully followed the unwritten rules of sound storage management: Save your most frequently accessed data on disk and your backup and archive data on tape.
How things have changed. Storage is now one of the more dynamic sectors in the information technology market, and the user management practices that apply and capitalize on innovations are undergoing equally rapid transformation.
The challenge now is to identify the noteworthy technologies vs. the ones that organizations can safely ignore. The ensuing analysis discusses four storage technologies that have recently gained traction in the market.
We also asked several experts to rate the importance of the technologies on a scale of 1 to 5, with 5 being of highest importance to storage managers and 1 being lowest. Of course, the ultimate importance depends on the needs and operating style of the organization that evaluates them.
1. MAID: Massive Array of Idle Disks
In the MAID world, organizations power off disk drives when users are unlikely to access the data, thus extending the effective life of the disk drive and reducing the long-term total cost of ownership.
Copan Systems has been the primary promoter of MAID technology. The company has been shipping the arrays since 2004, and the technology has won some customers among large enterprises that have high volumes of archival data. Using MAID, organizations can keep archival data on disk so that users can retrieve it quickly when necessary. Otherwise, they would relegate that data to tape or second-tier online disk. The former saves money but is cumbersome and slow to access, while the latter costs more money but is quickly and easily accessible.
Copan officials contend that MAID’s ability to extend the life of disk drives and lower energy consumption reduces the long-term costs of Serial Advanced Technology Attachment disk storage to a level competitive with tape.
The company’s reasoning is essentially sound but needs some qualification, said Stephen Foskett, director of strategy services at storage integrator GlassHouse Technologies. “Most companies don’t include disk failure, energy costs and some of these other factors” in their cost analysis, he said.
Organizations shouldn’t decide to pursue a MAID solution based solely on costs, however. “Even if the costs are not quite as low as tape, the advantages in terms of fast access and retrieval make it worth considering if you are a big organization with massive archiving needs,” said Mike Karp, a senior analyst at Enterprise Management Associates.
Analysts’ importance rating: 3.
2.SBOD: Switched Bunch of Disks
SBOD involves embedding what amounts to a Fibre Channel switch on a chip and placing it inside a storage system between the disk arrays’ storage controller and disk drives. That enables a direct link between the controller — the brains of the storage system — and any particular drive in the array.
“It is more reliable than arbitrated loop,” said Joel Leider, chief executive officer of Winchester Systems, which has been offering SBOD as an option with its FlashDisk arrays for the past year.
Arbitrated loop, the traditional method of connecting drives inside a storage array, connects the drives serially in a long string. If a drive begins exhibiting problems, identifying and diagnosing the problem can be difficult, Leider said. The number of attached disks and, hence, the length of the arbitrated loop also affect the overall performance of the disk array.
“This is really about cleaning things up on the back side of the array,” said Greg Schulz, a senior analyst at Storage IO. “By getting rid of arbitrated loop, you reduce the cost of support and you get some performance and scaling advantages. It also lets you pack more drives into the cabinet.”
Analysts say SBOD will appeal most to organizations looking for Fibre Channel arrays consisting of 32 or more drives.
Analysts’ importance rating: 3.
3. Perpendicular disks
Perpendicular disk refers to technology that enables manufacturers to increase the capacity of disk drives. It works by standing the magnetic bits that record data on their edges instead of laying them flat on the disk surface.
“Without technology like this, disk drives would have hit the capacity wall,” Schulz said. “This is something every storage manager should be interested in since there is no obvious replacement to magnetic disk drives at present.”
Using perpendicular disk technology, vendors have pushed disk drives to 500G. “I don’t see any reason why disks can’t hit 1 terabyte in capacity with this technology,” Schulz said.
“Perpendicular recording can increase the density of drives up to 10 times on the same media,” Foskett said.
However, super high-capacity disk drives have pros and cons. One advantage is a lower cost of storage per gigabyte. A disadvantage is greater risk. When a 500G drive fails, organizations could lose a lot more data than if a lower-capacity disk fails.
Data protection schemes such as Redundant Array of Independent Disks (RAID) can also become problematic as drive capacities increase. The reason is that it can take a long time to rebuild a very large drive using the popular RAID 5. “That’s why companies are turning to other forms of RAID,” Karp said.
For example, RAID 6, an extension of RAID 5, enables additional fault tolerance by using a secondary data-protection technique. RAID 6 can absorb multiple simultaneous drive failures, which is more likely because of the extra time it takes to rebuild the large drives in the event of a failure.
Analysts’ importance rating: 5.
4.USB thumb drives
USB thumb drives are — you guessed it — the thumb-sized devices that plug in to the USB port and can store gigabytes of data. Any USB-capable device can use them. For IT groups, these devices can be a blessing or curse.
As a blessing, the devices provide an inexpensive means of transporting data from computer to computer. One public high school librarian uses a thumb drive to back up the entire library system each evening and takes it home in her purse, eliminating the cumbersome, tedious tape backup routine.
The curse is the security risk they pose. “My concern as an IT person is that anybody can take gigabytes of corporate data off the premises in their pocket,” said Dianne McAdam, director of enterprise information assurance at the Clipper Group.
“Although the portability is great, the devices pose a huge risk in terms of data protection and data privacy,” Schulz said.
To address those security concerns, some vendors offer thumb drives that use security algorithms to encrypt their contents, which are then password protected.
Thumb drives are also starting to become a popular carrier of users’ personal application software, which they can take with them to run on any available computer.
Analysts’ importance rating: 5.
Radding is a freelance journalist based in Newton, Mass. He can be reached at [email protected].