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What is RAID? How to avoid NAS data loss.

Here’s everything you need to know about RAID.

There’s always the possibility of failure with anything in life and a storage drive is no exception. When using mechanical drives, you’re more prone to failure due to all the moving parts inside the device. This is where a redundant array of inexpensive disks (RAID) comes into play and I’m going to run you through what it is and why you should care.

What is RAID?

RAID is precisely what the acronym describes. It’s the formation of the best NAS drives into a single volume. While this does not automatically provide protection, there are RAID types that involve the duplication of data across disks to avoid data loss in the event of a drive failure.

If a drive fails and it’s not part of a RAID configuration, you’ll run the risk of losing stored data. If a drive fails in a RAID and needs to be replaced, the stored backup data could then be used to recreate the storage volume, allowing you to continue as if nothing happened.

RAID does mean you lose some of the capacity due to part of the volume being reserved for storing the necessary data for use in recovering the volume. This is a price worth paying for the protection.

Why you should use RAID on NAS

RAID on NAS is incredibly important. These devices can hold terabytes worth of data and you need to make sure it’s protected against drive failure. While I always recommend having more than one backup copy of data, it’s better to have the means to recover your NAS without relying on external backups.

I’ve compiled a list of the most popular RAID configurations for NAS enclosures in the table below.

RAIDMinimum drivesTolerable drive failuresData redundancyCapacityNotes
Basic10HDD sizeNo protection
SHR10-2VariesNo protection with single drive SHR
020HDD sizeNo protection
121-3HDD # -1 x smallest HDD size
531HDD # -2 x smallest HDD size
642HDD # -2 x smallest HDD size
1042+HDD # -1 x smallest HDD sizeHDDs must be an even number
Tolerable to half the number of HDDs

Using the above table as a guide, I would recommend using either SHR (if using a Synology NAS) or at least RAID 1 to ensure your drives are configured in a way to avoid data loss.

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By Richard Edmonds

I've been covering the tech industry for more than a decade and have tinkered with NAS for just as long. Follow my ramblings and more right here on NAS Master!

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