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(also Enhanced RAID 5E)

RAID 5EE definition

RAID 5EE is an extension of the RAID 5E configuration. It incorporates the features of RAID 5E, but with better spare drive features. It’s a method of organizing multiple hard drives in a computer to improve data protection and performance. RAID 5EE distributes spare space across all drives to allow immediate use of the spare capacity. It makes computers faster and safer, however, it's not something every regular user needs – RAID 5EE is mostly used in larger setups where data security and speed are critical.


The decision between RAID 5 and RAID 5EE hinges on specific requirements for rebuild speed, system performance, and hardware or controller compatibility. Here's how they compare:

Data handling:

  • RAID 5 stripes data across drives and uses parity for fault tolerance — parity information is evenly distributed among all drives.
  • RAID 5EE is similar to RAID 5 in striping data and parity, but it also integrates a distributed hot spare into the array.

Fault tolerance:

  • RAID 5 can recover information from a single drive failure, using parity data for reconstruction.
  • RAID 5EE also tolerates a single drive failure, using both parity data and the integrated distributed hot spare for quicker recovery.


  • RAID 5's read operations are usually efficient, but write operations involve calculating and recording parity data, which can make them a bit slower.
  • RAID 5EE offers better write and rebuild performance than RAID 5, mostly because the distributed nature of the spare space helps it recover data faster.


  • RAID 5 dedicates the equivalent of one drive's capacity for parity. For instance, in a three-drive setup, usable space is the capacity of two drives.
  • While RAID 5EE also has parity overhead similar to RAID 5, the array optimizes the use of available capacity by distributing the hot spare space across all drives.

Rebuild process:

  • In case of a drive failure, RAID 5 rebuilds data from the remaining drives using parity data. This process may take some time, especially in large arrays.
  • RAID 5EE offers a faster rebuild process because of the distributed hot spare. The system starts rebuilding immediately after a failure without waiting for a separate spare drive to be brought online.