Industry Trends and Perspectives: RAID Rebuild Rates

May 26, 2010 – 9:52 pm

This is part of an ongoing series of short industry trends and perspectives blog posts briefs.

These short posts compliment other longer posts along with traditional industry trends and perspective white papers, research reports, solution brief content found at

There is continued concern about how long large capacity disk drives take to be rebuilt in RAID sets particularly as the continued shift from 1TB to 2TB occurs. It should not be a surprise that a disk with more capacity will take longer to rebuild or copy as well as with more drives; the likely hood of one failing statistically increases.

Not to diminish the issue, however also to avoid saying the sky is falling, we have been here before! In the late 90s and early 2000s there was a similar concern with the then large 9GB, 18GB let alone emerging 36GB and 72GB drives. There have been improvements in RAID as well as rebuild algorithms along with other storage system software or firmware enhancements not to mention boost in processor or IO bus performance.

However not all storage systems are equal even if they use the same underlying processors, IO busses, adapters or disk drives. Some vendors have made significant improvements in their rebuild times where each generation of software or firmware can reconstruct a failed drive faster. Yet for others, each subsequent iteration of larger capacity disk drives brings increased rebuild times.

If disk drive rebuild times are a concern, ask your vendor or solution provider what they are doing as well as have done over the past several years to boost their performance. Look for signs of continued improvement in rebuild and reconstruction performance as well as decrease in error rates or false drive rebuilds.

Related and companion material:
Blog: RAID data protection remains relevant
Blog: Optimize Data Storage for Performance and Capacity Efficiency

That is all for now, hope you find this ongoing series of current and emerging Industry Trends and Perspectives interesting.

Ok, nuff said.

Cheers gs

Greg Schulz – Author Cloud and Virtual Data Storage Networking (CRC Press), The Green and Virtual Data Center (CRC Press) and Resilient Storage Networks (Elsevier)
twitter @storageio

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