How many disks can fail in RAID 5?

Written by


Approved by

Anish Kumar

Posted on
June 14, 2019


If you want to work as a storage administrator, you should possess good knowledge about one of the advanced data protection technology i.e. RAID and its levels in detail. Reason for this is that RAID technology acts as a perfect set to provide protection against various HDD failures. According to the experts of Data Recovery […]

Disk Failure in RAID 5

Now, the main question that comes in our mind is how many numbers of the disk may fail in RAID 5. For this, experts involved in RAID Data Recovery have said only a single disk failure is desirable in RAID 5. This is because; if more than one disk fails simultaneously, RAID 5 cannot able to retrieve the data. To understand the logic we should
discuss the mentioned terminologies in detail.


RAID refers to the collection of multiple disks responsible to define the predefined numbers of disk blocks addressable in a contiguous way. Experts of Hard Drive Recovery called these disk blocks as strips, while aligned in multiple disks to form a stripe.

Mirroring Technique

According to the technique of mirroring, you simply create a mirror copy of strips/disks to protect them and thereby, get two different copies of important data. In the case of failure, the controller uses the second disk for recovery of the data.

Parity Technique

Experts involved in Server Data Recovery or RAID 5 Disk Recovery have come up with another affordable data protection technique i.e. Parity technique. Accordingly, parity adds an additional HDD to the existing stripe width for holding the parity bit. Parity refers to a redundancy check to make sure about the complete protection of data without any requirement to maintain a complete set of duplicate data. Accordingly, whenever a disk fails, experts calculate the missing value by subtracting from the sum of other elements from the value of parity bits.
Therefore, based on the concepts, we should say that only 1 disk failure is allowable in case of RAID 5.

Categories : Blog, RAID Data Recovery,

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