For the longest time data duplication through mirroring or other schemes was regarded as the safest form of redundant data protection. What reenforced that view was the fact that traditional RAID systems using parity based protection are an all-or-nothing type of deal.
That is, with traditional parity based RAID systems, if the said systems are unable sustain and recover from a particular failure level then all data is lost. This chronically negative aspect of traditional RAID systems has lead to the doctrine of “RAID is not backup”.

Mirroring is simple.

Here is an example of a mirroring system:

And here is an example of a parity based system:

As you can see, it is much simpler to implement a mirroring scheme than a parity one. Mirroring involves simply copying the data to two disks where parity based schemes involve algorithms for computing the parity and for where to write the data and parity.

Looking beyond simplicity… understanding the importance of tolerance level

Yes, mirroring is simple an inherently easier to make robust. However, parity based systems are just as robust when properly implemented. If all schemes have the same robustness when properly implemented, then we need to focus on the real differentiators. The biggest factor when it comes to data protection is tolerance level, which is the number of failure the system can tolerate and successfully recover from.

Mirroring has a tolerance level of only 1

The typical mirroring system can only tolerate a single failure as there typically only exist two copies of the data. Lose both copies and you have lost it all.

Mirroring is expensive

Mirroring requires double the amount of space used to store the data. This turns, for instance, a $1k system into a $2k system, and things add up really quick.

Evolution in data protection

Parity based schemes can be extremely cost efficient. For instance, if you have a million 2TB drives, it only take one additional 2TB drive to provide protection to all those 1 million drives.
For all the benefits that parity based schemes provide, their core drawback has always been and will remain a hard pill to swallow: you lose all your data if things go wrong.

We have evolved, and now comes FlexRAID to the rescue.
FlexRAID gives you the benefits of parity based schemes without the risk of losing all of one’s data unless you lose every single one of your drives.
FlexRAID allows you to choose and pick your protection level going from 1 to infinity.
That’s right, your protection level under FlexRAID is limited only by your choice and by your own hardware.

Conclusion

Do no waste your time with any product that relies on duplication as a protection scheme for your precious data.
Great technological progresses have been made and you should no longer be doing things the hard and expensive way.
When it comes to data protection, do it the FlexRAID way.