Midrange Morphology

Everyone needs more and better storage these days, so it should come as no surprise that midrange SAN systems are starting to look like high-end "mini-me's" or that choosing one is getting to be an enterprise-sized task.

Indeed, the growing diversity of features and functions testifies to a market that's robust enough to foster lots of competitive activity. Companies are storing more data than ever before. Vertical markets like healthcare have fostered massive storehouses of digital images – which can't be thrown out, ever.

And speaking of throwing things out, much enterprise data – over 60 percent of it, by most assessments – is in the form of unstructured email and Microsoft Office documents. This kind of corporate flotsam, which used to be trashed regularly, might now be required to defend a company's innocence or prove its guilt.

This fresh demand for networked storage is converging with a ready supply of new, cheaper disk hardware, such as new SATA drives. At the same time, trends such as 4-Gbit/s Fibre Channel, iSCSI SANs, and virtualization are increasing the number of factors that IT managers look for in new systems.

These variables make for a dizzying array (no pun intended!) of midrange SAN choices. Systems can be purchased in a capacities of less than 1 Gbyte to more than 150 Tbytes. They support iSCSI, Fibre Channel, Ficon, and other protocols through a range of physical interfaces, including Gigabit Ethernet. Prices can range from $10,000 to more than $150,000. Software options, often offered through partnerships with other vendors, include device management, remote replication, snapshotting, and clustering, to name just a few.This is all good news to IT managers who were formerly forced to poke into the domain of high-end storage to meet their organization's requirements. They no longer need to buy too much storage or pay for high-end features they didn't need. On the downside, they're forced to make some tough choices, in a field where suppliers are getting ever fancier and more glib about their distinguishing characteristics.

Take performance measurements such as I/O or throughput. Are they taken from the input or output side of the machinery? Are they based on file- or block-oriented activity? Do they involve caches, or not? At burst or sustained rates? Who conducted the tests, and with what equipment?

"It's a big snarl. Performance figures are virtually meaningless," said one supplier interviewed for this month's Byte and Switch Insider report. After three days of conversations about metrics like the aforementioned, it was easy to agree.

So where does one begin the selection process? With the basics, most sources suggest. Since most companies looking to buy midrange SANs want modularity, it's important to look at capacity and how much hardware, of what size, is required to scale it. The number of host ports, types of interfaces, and LUN counts also provide a jumping-off place.

There are other choices, too. While SATA disks provide a cheaper alternative to traditional Fibre Channel ones, they aren't reliable enough for most transaction processing. And in the realm of software, it's important to scope out whether functions such as remote replication or snapshotting will enhance a customer's storage network, or simply add to its cost.These simple distinctions are only the start. Beyond the basics, IT managers will no doubt want to test any systems they're considering, given the level of hoo-hah this active space has generated.

Any research in this area will be well worth the effort. The midrange SAN market has become one of the hotbeds – and testbeds – for emerging features and functions. As data needs grow and SAN technology expands to meet new requirements, the midrange will be the proving ground for storage networking.

— Mary Jander, Site Editor, Byte and Switch

Midrange SAN Systems: A Morphing Market is available as part of an annual subscription (12 monthly issues) to Byte and Switch Insider, priced at $1,350. Individual reports are available for $900.

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