Data Centers

The future of storage is 'virtually' assured

Columnist Tim Landgrave details how a new product promises not only an easier interface for storage systems but improved management configurations. The advances will very likely change how you view and manage storage.


At a recent technical conference, I spoke to the former CIO of an applications hosting company. He related an experience from the company’s early days. The engineers set up its first storage array (from a well-known, top-three storage vendor) with no incidents or issues. As the company grew, it had the normal growing pains of reformatting new blocks of storage and moving data around.

One day, as an engineer toiled to format a new section of storage, he inadvertently translated the hexadecimal number 10 (decimal 16) to the hexadecimal number A (decimal 10). With just one press of the [Enter] key, he wiped out an entire storage array and a complete day of work for all the company’s customers.

Unfortunately, this scenario is more common than most realize. The difficult, and unwieldy, interfaces on most storage systems are as arcane as the storage configurations they attempt to manage. But a little-known hardware company and a well-known software vendor are making significant changes in the way we’ll view and manage storage in the future.

Virtualizing storage
Xiotech, a division of Seagate Technology, has been developing unique storage virtualization technology since 1998. Given Seagate’s desire to sell more hard drives to competing storage system manufacturers, Xiotech has never had the budget, or the corporate support, to let corporate customers know about its products. But after spending an afternoon with one of its field technicians and reviewing its Magnitude storage system, it’s clear to me that Xiotech has solved problems that EMC, Compaq, and others promise to solve during the sales cycle but don’t deliver on installation.

With most storage systems, the configuration of redundant storage on the storage array has to directly mirror the physical dimensions of the storage array itself. In other words, if you want to configure a RAID level 5 array using three partitions of 100 GB each (for a total of 200 GB of redundant storage), you must have 100 GB free on three physical drives in the storage system. If the storage isn’t available, the administrator has to reconfigure the array to create the necessary configuration.

The Xiotech system uses a different approach. Xiotech’s technology combines all the disk drives in the storage system into a pool of shared storage. Administrators can add, remove, expand, or relocate storage allocated to individual servers on the fly and in a matter of seconds. Rather than being bound by drive geometries, the Magnitude system allows you to use disk drives of different capacities and speeds simultaneously. You can even change RAID levels while the system is online and add storage without having to bring the system offline. All of this is accomplished with an intuitive interface that minimizes the possibility of wiping out an existing storage area.

Xiotech’s storage system makes it simple to consolidate servers and storage. Its ability to boot directly from the storage system, combined with the dynamic partitioning and mirroring capabilities, gives the system some unique capabilities. For example, one of the most challenging issues faced by systems developers is the inability to adequately maintain a certification or testing environment. With the Xiotech system, the process is simple and seamless. Using the dynamic mirroring capability, you can add a mirrored partition to an existing system and allow the mirror to build. Once built, you can break the mirror—reassign the mirrored partition to boot from another server and conduct testing on an exact duplicate of the production environment. This also works well for service pack or new version testing for packaged software. This dynamic reconfiguration is only one example of the benefits of virtualized storage.

Cost
When it comes to storage configuration, there’s no set pricing; it depends on the configuration. A 500-GB system ranges in price from $40K to $60K, depending on features and options included.

Although Xiotech is the first company to offer this kind of flexibility, I expect that other companies will also find ways to offer similar technology. The only issue then will be how far Xiotech will have moved ahead by the time they release their comparable features.

Shadowing storage
Many of the features necessary to manage a storage array efficiently will be moved from the proprietary hardware controllers of the storage vendors and into the operating system drivers from companies like Microsoft.

In fact, with the next release of Microsoft Server operating systems (Microsoft .NET Server 2003), one of the most requested disk storage features will be offered through software drivers from Microsoft. And this isn’t the first time Microsoft has offered this kind of functionality. Windows 2000 already has built-in software mirroring and RAID capabilities that allow companies to build redundancy into their system deployments without investing in expensive hardware controllers.

The .NET Server adds a new service called the Volume Shadow Copy Service (VSCS). VSCS works with the underlying operating system to create a complete point-in-time backup image without requiring users to log off. The service can include open files in the shadow copy, and it maintains consistency within the files. Once the shadow copy is completed, administrators can back up the shadow copy and delete the shadow copy volume to recover the disk space. Of course, with the rapidly falling price of disk storage, many companies will keep multiple generations of shadow copies online and only roll them to tape when they need to recover disk storage. Using VSCS, administrators can use off-the-shelf backup hardware and software products that have been certified for use with the service. And one of the products certified for use with VSCS is the Xiotech Magnitude system.

The unique combination of Xiotech technology and new Microsoft disk management technology in .NET Server will give system administrators new ways to keep their systems online while guaranteeing the integrity and recoverability of the data they manage.

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