SAN file systems are a great idea, if you can afford one. They enable multiple users simultaneous access to the same file, but the price tag for this functionality, which includes sophisticated stuff like multi-platform data sharing, policy-based provisioning and file-level locking, is outrageously steep.
For example, the starter pack for IBM's SAN file system costs $90,000, while Advanced Digital Information Corp. (ADIC), considered one of the cheaper options, charges between $3,000 to $5,000 per node.
Apple Computer, Inc. plans to undo this notion of expensive storage software with the launch of its Xsan SAN file system this fall, for just $999. It's also worth noting that Apple doesn't charge more when you add extra storage to the SAN.
"Our users have been duplicating data or attaching an Apple Xserve RAID box to each server because the SAN file systems out there were too expensive, and we didn't have a solution," said a spokesman for Apple. With Xsan, storage management is centralized, users can have access to the same files, and it's an affordable option, he said.
The Xsan software runs on a metadata controller that works like an out-of-band appliance, or traffic cop that knows where everything is on the SAN and performs all the authorizations and policy management. The file system holds 16 TB of data and up to 64 clients can read and write to shared storage at the same time. Among other features, it offers Fibre Channel multi-pathing and bandwidth reservation, which sets aside a reliable amount of bandwidth for applications that need to write a heavy chunk of data to disk. And storage managers can reserve capacity for a particular user or group and create hard and soft quotas.
Xsan is interoperable with ADIC's StorNext SAN file system, which enables Apple to work alongside Windows, Unix and Linux machines. And it supports ADIC's Scalar line of tape libraries and policy-based data management tools for ILM (Information Lifecycle Management) purposes.
Apple has also announced a 2 Gbit Fibre Channel PCI Express card to connect its Xserve RAID array to its servers. In keeping with its pricing model, it is charging just $499 for this card, which is half the price of traditional HBAs.
Apple is hoping that between its low-cost SAN file system and cheap PCI Express card, it will start to attract users that are not already Apple shops. However, it realizes this will be an uphill struggle. "We're the iPod company; it's hard competing with our own marketing sometimes," the spokesman said.
Peter Gerr, senior analyst with Enterprise Strategy Group, noted that most users are unlikely to hire Apple to design a 5,000-port SAN, just like they wouldn't look to IBM to design a cool walkman or handle post production on a movie. However, he said Apple's pricing is a departure from its usual model. "They tend to command premiums, and users are typically ready to pay more for the luxury of using well-made equipment … This pricing will turn heads, but there is more to changing the ebb and flow of the storage industry than dropping your price."