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Method and System for Reducing Read Overhead in a Redundant Array of Inexpensive Disks

IP.com Disclosure Number: IPCOM000237785D
Publication Date: 2014-Jul-10
Document File: 3 page(s) / 189K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method and system for reducing read overhead in a redundant array of inexpensive disks.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 51% of the total text.

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Method and System for Reducing Read Overhead in a Redundant Array of Inexpensive Disks

Disclosed is a method and system for reducing read overhead in a redundant array of inexpensive disks (RAID).

In an exemplary embodiment, a RAID protected storage system includes a RAID controller. The system also includes a plurality of storage devices connected and managed by the RAID controller. The RAID controller is used to protect against failure of devices by generating and maintaining redundant parity data in one or more of the attached storage devices. The parity data is an arithmetic or logical function of the data residing on other storage devices connected to the same RAID controller.

FIG. 1 illustrates a RAID 5 storage system described herein,

As shown in FIG. 1, RAID storage system includes 5 storage devices with 4+p protection scheme in which one of N storage devices stores the bit-wise logical XOR of data residing in other N-1 storage devices. The 4+P protection scheme describes four logical data pages corresponding to four storage devices and a fifth logical data page is a combination of logical XOR of remaining four logical data pages. On performing a write operation over a specific storage device, parity data associated with the respective storage device is also changed. Additionally, if any one of the storage devices in the system is failed, the stored data is not recoverable. But the lost data can be recovered by calculating logical XOR of data residing in the other 'N-1' storage devices.

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FIG. 2 illustrates an exemplary scenario of RAID storage system described herein,

As shown in FIG. 2, a write operation is performed by an external interface connected to a RAID cont...