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Recover IBM RAID 5EE

Hardware and RAID Configuration

There were 3x1-TB drives in a RAID 5 setup. The drives were taken out of a 4-drive NAS whose brand the customer did not specify. (We usually do not ask for this information.) The fourth drive was damaged beyond repair.


The customer did not provide any detail other than that “the shared data was inaccessible.”


  • RAID rotation analysis indicated the parity rotation is unlike a standard RAID 5 (i.e., backward or forward, symmetric or asymmetric). Each row contains two data blocks much like a RAID 6.
  • Metadata found on the drives suggested this was an XFS-formatted volume.
  • Further rotation analysis identified this as an IBM RAID 5EE. Under this scheme a 4-drive RAID 5 is equivalent to a standard 3-drive RAID 5 with a hot spare drive. However, in a RAID 5EE the spare drive also participates in the rotation.


  • Although File Scavenger® no longer provides native support for RAID 5EE (due to lack of demand), it provides a much more powerful tool: custom raid rotation schema. This function gives the user virtually unlimited ways to define a RAID with any possible rotation scheme.
  • With a custom RAID schema created for this particular RAID, File Scavenger® quickly found the XFS volume and restored its contents. `


All files were completely restored with the correct name and folder structure.

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