How to recover data from NAS configured as RAID 5

RAID 5 array combines striping and parity techniques. The data is divided into blocks and written to the RAID 5 member disks. A certain checksum is also calculated and written to one of the disks in each row of blocks. It is called the parity function and is determined based on the data of other disks in a row. This parity provides data redundancy; that is why it is possible to recover the data in case of disk failure.

There are four types of RAID 5 arrays: right and left, asynchronous and synchronous.

RAID 5 Left Synchronous RAID 5 Right Synchronous RAID 5 Left Asynchronous RAID 5 Right Asynchronous

A RAID 5 array requires a minimum of three disks. Therefore, a fault-tolerant RAID 5 cannot be created in a 2-disk NAS. If one of the RAID 5 member disks is damaged, the NAS runs much slower than usual because that disk's data must be recalculated from data blocks on the other disks. A RAID 5 NAS is designed to be hot-swappable in the event of a disk failure; however, in fact, users often lose their data in the process.

DIY file recovery for RAID 5 NAS devices

If you only want to recover deleted NAS data, connect to the NAS using ReclaiMe NAS Recovery software. You can get your data back without taking out the disks. Simply download the software to your PC, double-click your NAS, enter your login and password in the window that opens, select the NAS volume, and click the Start button. You can find a more detailed procedure on the – How to recover deleted files from a NAS drive page.

If the NAS fails, data recovery will take more time and effort. You will have to take the disks out of the NAS and connect all the disks to a computer running Windows.

After connecting successfully, launch ReclaiMe NAS Recovery software and scan the volume of the NAS device. You can find the detailed instructions and videos on the NAS recovery page.

You may also encounter a much more complex case – a corrupted RAID5 configuration. In this case, you first need to recover the array configuration using another software – ReclaiMe Free RAID Recovery. You need this software if you cannot find the NAS volume in ReclaiMe NAS Recovery.

A RAID5 array configuration consists of:

  • number of member disks,
  • which disk comes first in RAID 5 array,
  • disk order,
  • block size,
  • start offset,
  • parity location.

To restore RAID 5 configuration, you need to:

  1. Install and run ReclaiMe Free RAID Recovery on a Windows PC.
  2. Select all available array member disks and click the Start RAID 5 button. Please note that ReclaiMe Free RAID Recovery can recover RAID 5 parameters if one of the array member disks is missing.
  3. After successful recovering the RAID 5 parameters, open ReclaiMe File Recovery software to restore the files. You can find more detailed instruction on the How to recover RAID5 page.

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