Definition - What does RAID 5E mean?
RAID 5E is a type of nested RAID level that is similar to RAID 5, but includes an integrated hot spare drive.
The E in RAID 5E stands for "extended" as it adds on or extends the capabilities of RAID 5. The extended spare drive is part of the overall RAID 5E and can be used for input/output operations.
Techopedia explains RAID 5E
The addition of a hot spare drive within RAID 5E helps in distributing I/O load or operations, resulting in better performance than RAID 5. The hot spare drive created within the RAID 5E can only be used within the same array, not any other RAID 5 or 5E array.
This spare drive usually remains idle and is used when a drive in the array fails. RAID 5E stripes data and parity information over all the drives within the array. RAID 5E can be created with a minimum of four drives and a maximum of sixteen drives in a single array.