While industry experts say the shape of RAID has evolved and is handled differently than when it first appeared 20 years ago, the core concept of combining drives to protect data lives on regardless of the methods used.
"Is RAID still relevant? Absolutely. Is RAID still important? Absolutely. Is RAID losing its buzz, lustre, sex appeal? Yeah," says Greg Schulz, founder and senior analyst at StorageIO Group. "What's taking its place? Distributed RAID, global RAID, hybrid RAID. We're seeing all of these new manifestations of RAID."
Experts say storage systems conceived during the last five years or so from Compellent Technologies, EqualLogic (now part of Dell), LeftHand Networks (now part of HP) and 3PAR use alternatives to traditional RAID, such as distributed parity schemes and wide striping.
EMC's Atmos and IBM's XIV Storage System are new versions of storage systems that use distributed parity. Other systems that hit the market in 2008 use new technologies to avoid RAID rebuilds. There's disagreement in the industry over whether those systems are RAID or not, but Schulz says it doesn't matter to the people who use them.
"Most people understand RAID and relate to RAID," he says. "If they hear about a new scheme, they don't care if it's RAID. They say, 'Is it good? Is it reliable? Can I trust it? Is there overhead?'"
Andrew Reichman, senior analyst at Forrester Research, says RAID is becoming more application-specific. For example, Oracle Automatic Storage Management (ASM) does its own software-based mirroring for data protection and requires no hardware RAID. "So hardware RAID may be de-emphasised for apps that have native data redundancy, but data redundancy of some kind will always be a part of the overall data protection arsenal," says Reichman.
One type of RAID that's increasing in value is RAID 6, which provides dual parity that makes it possible to recover from two disk failures simultaneously. That's a critical feature for organisations that use large capacity drives, particularly SATA.
Schulz says RAID is too embedded in storage technology to go away, but will continue to undergo fundamental change. "Look at all the activity around RAID 6, good, bad and indifferent," he says. "Will we see RAID 7 or RAID 8? I don't know. There's more noise around a distributed parity scheme.
"RAID is a commodity," adds Schulz. "The newer approaches tend to be more interesting. But that doesn't mean we're moving away from traditional RAID."