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Is RAID Good For Backup?

RAID stands for Redundant Array of Inexpensive Disks. It offers reliability and helps protect against individual disk failure. It also offers faster access to data, too. It is most often implemented in dedicated file servers and network attached storage devices in large businesses. However, RAID itself does not function as a backup facility. It does not protect you if a file is deleted or overwritten. To explain this, it is important to understand how RAID works.

RAID uses multiple drives and mirrors the data across the drives. This means that if one drive fails then the system will stay up and there will be no data loss or downtime. If a single disk fails then it can be removed and replaced with ease (as long as the server offers support for hot-swappable hard drives). There are different numerical levels of RAID. For instance, RAID 5 has more protection than RAID 1 because it uses at least three drives. The fault tolerance that RAID offers can be a great benefit to business.

RAID also allows for faster access to data. With a RAID there are multiple drives and the data can be accessed in parallel, meaning that it isn’t limited to a single read/write mechanism of one drive. If a lot of users are accessing the data at one time then it will become very apparent just how beneficial having a RAID is.

However, just because your data is on multiple drives does not mean that RAID is suitable backup solution. It is essentially all just on one drive. Although it offers hard drive failure tolerance, it still is not a backup. For example, if your drive is infected with a virus, you cannot restore to a RAID like you would be able to with a backup. Also, if you accidentally delete or overwrite a file then you will not be able to get it back in the RAID as all actions are mirrored across the drives.

A good backup should not be kept on the machine of the data that you are backing up. It would be much more sensible to have a backup offsite if possible. When using a RAID, if all your files are removed for whatever reason (whether that’s down to anything like user or software error), then the copies of your files will be deleted along with the originals. RAID does not solve this problem like good backup solutions do. A backup solution should also allow you to restore data from multiple points in time, whereas a RAID doesn’t allow you to roll back.

RAID protects against disk failure, but not against things like physical destruction or user error due to the way that the data is mirrored across all the drives. As such, it is not suitable to use RAID as a backup solution. It is, however, great for reliability since it stops individual disk failure and to speed up data access. Using a RAID in pair with a good backup solution, whether it be something like an external hard drive or cloud storage, is your best choice.


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