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Comprehensive Guide to RAID Array Recovery

June 24, 2014

This guide shows our process for a typical RAID data recovery case. If you need to recover files from a RAID or SAN, call 1.800.237.4200 to speak with a specialist.

Step One: Cloning Each RAID Member as a Raw Image

Before attempting recovery or analysis, our engineers need to protect RAID media from potential damage. We clone all working discs into large raw images. This ensures that the RAID data is recoverable even in the unlikely event of subsequent media failures or failed recovery attempts.

We verify all disk images before proceeding to the next step, then create additional backups of the raw images on a storage server. These backups are also verified.

If a RAID has one or more failed disks, it progresses to step two. If the RAID has logical issues, we proceed to step three.

Step Two: Recovering Failed RAID Media

Some RAID media is inaccessible, and when this is the case, our engineers need to work in a Class 5 clean room to diagnose and repair the problem.

Many hard drives contain failed heads, which must be removed from the hard drive and replaced. engineers can use specialized equipment to read each platter, creating a raw image that can be used in the next stage of recovery.

When creating disk images of damaged hard drives, we need to remove bad sectors that were marked as such when the drives were manufactured. If we do not remove bad sectors, data slippage will occur, and the recovered data will not be usable. has developed a number of tools that allow engineers to easily locate bad sectors on individual hard drives, preventing data slippage and allowing for a more efficient RAID data recovery process.

After we create a functional set of disk images, our engineers can move on to step three.

Step Three: Analyzing the Clone Images

The next step requires a thorough analysis of all images to ensure that they are identical to the original media. This will allow our engineers to successfully recreate the RAID volume using special software tools. developed many commonly used tools for RAID recovery, but without a thorough analysis, recovery attempts will often fail.

This step can vary from case to case. We make sure that data and parities (where applicable) are consistent. We compare data across all disk images to make sure that complete files are present. If a rebuild was carried out on the array, we check to see whether data was overwritten. We review the analysis and then proceed to step four.

Click here to view steps four through six of our comprehensive guide to RAID data recovery.