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RAID levels: Learn about RAID 50

RAID 50 combines striping with distributed parity for higher reliability and data transfer capabilities. Learn more about this RAID level in this short educational tip.

What you will learn from this tip: How RAID 50 combines striping with distributed parity for higher reliability and data transfer capabilities.


Like the other double-digit RAID levels, RAID 50 is a combination of two basic RAID techniques. It combines striping (RAID 0) with independent data disks with distributed parity (RAID 5). It stripes data across at least two RAID 5 arrays.

The easy way to think of RAID 50 is as RAID 5 with an extra pair of suspenders. RAID 50 offers increased write performance and better data protection, including faster rebuilds, than RAID 5 in the event of a disk failure. While performance degrades in the event of a disk failure, it doesn't degrade as much as it would in a RAID 5 array because a single failure only affects one of the arrays, leaving the other fully functional. In fact, RAID 50 can sustain up to four drive failures if each failed disk is in a different RAID 5 array.

RAID 50 is best used for applications that need high reliability, and that need to handle high request rates and high data transfer with lower cost of disks than a RAID-10 (striped and mirrored) array. However it takes a minimum of six disks to set up a RAID 50 array.

One of the disadvantages of RAID 50 is that, like RAID 5, it needs a sophisticated controller. For maximum throughput, a RAID 50 array should have synchronized disks, which limits disk choices since not all disks can be synchronized.

For more information:

Tip: RAID-10 -- Two great RAIDs that go great together

Tip: How to choose the right RAID for your array

Tip: A quick and dirty way to increase a RAID-5 array


About the author: Rick Cook has been writing about mass storage since the days when the term meant an 80 K floppy disk. The computers he learned on used ferrite cores and magnetic drums. For the last 20 years, he has been a freelance writer specializing in storage and other computer issues.

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