Generally speaking RAID storage is known for its systems that provide a certain amount of redundancy and can act as a backup in case something goes wrong. However how safe is the data on RAID storage really?
The answer to that is not as simple as you may imagine, and it really depends on the type or ‘level’ of RAID that is in use. Different levels of RAID storage use very different technology that impact how safe the data that is stored will be.
Mirroring and Parity
In simple terms, all types of RAID storage apart from RAID 0 use some form of mirroring or parity. The difference between mirroring and parity is a bit subtle – mirroring involves replicating data that is stored precisely, whereas parity involves generating a parity checksum that can be used to restore any data.
While both mirroring and parity provide a form of backup and act as a safety net in case something goes wrong with a particular sector or drive – the degree to which they do so can vary. For example RAID 5 uses a single parity system that can hold up when one drive fails, but RAID 6 uses double parity that allows it to hold up even when two drives fail.
Because of the differences between RAID levels, it is important that you choose the one that is most appropriate depending on how much safety is required for your data. Of course other factors may also play a part in your decision – such as performance as well as cost.
Still Room for Backups
Suffice to say while RAID storage (other than RAID 0) provide some sort of safety for your data – they are not entirely foolproof and in some cases you could still end up losing data. As such if you want to be really safe you should still backup data - preferably in a form that can be kept off-site so that it is also protected from natural disasters, fire, theft, and so on.
On top of acting as a final safety net, having a backup can also help to protect your data from any unwanted changes. Being able to ‘roll back’ data or restore it from a previous point is often useful in some situations, and is something that you can perform if you have a past backup available.
In short RAID storage is best viewed as one link in a system of measures taken to protect and secure your data. The good news is that if something untoward occurs you could look at options such as raid data recovery from Kroll Ontrack to help you to salvage some (or all) of your data.