RAID ALL THE THINGS | RAID 5 & 6

Here is what you need to know…

  1. RAID 5 one of the single most cost-effective arrays out there.
  2. This array offers one of the best performance.
  3. RAID 5 has what is called a parity.
  4.  RAID 6 contains two parities.

RAID 5 is the most common RAID type for business servers and enterprise devices. This is because it’s the best combination between performance and integrity.  The data is striped across the 3 drives. so each drive gets a piece of data and as you can get, this method is commonly used by RAID 0. Here is where this array separates itself from RAID 0.  RAID 5 uses what is called a parity. A parity  or parity block is raw data that is mean for recovery.

How does a parity work? Well, for each strip that occurs, one parity is written. (see below) Each parity belongs to a specific stripe. Which means that the strip has a backup, should part of the data become corrupted. If a drive were to fail, the parity could be used to rewrite all the precious data to the new drive. RAID 5 only has a fault tolerance on 1 drive. If two drives were to fail, the array would be gone along with most or all the data on the array.

Storage capacity is moderate with RAID 5. I would argue that a user or organization gets about 3 quarters of the space from the overall combination of the array.  It isn’t 100% because the parity does take up some storage space. RAID 5 does require a minimum of 3 drives and more can be added to increase the overall storage capacity.

software-raid-in-windows-8-1-with-storage-pools

Quite possible the biggest issue with RAID 5 is when being used on a server that performs a lot of write operations.  If the server performs a tonne of write operations there will noticeable lag.

RAID 6 is also commonly used in enterprise business and is considered to be almost identical to RAID 5. The only difference being that RAID 6 has two parities. This also allows it to have a fault tolerance of 2 drives. However, the array needs a minimum of 4 drives.

raid_6

As with all storage arrays, the disks must be the same size. Otherwise, the array will only use the minimum amount of space that is equal to the smallest drive. If you have a 500GB drive and a 1TB drive, both drives will use a combined space of 1TB and not 1.5 TB.

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