Storage devices fail, and redundancy is the key strategy for maintaining access to critical data when hardware breaks down. This content covers how redundancy works, why it matters, and how technologies like RAID and disk mirroring protect against data loss.
Storage Redundancy
Do you know what the problem is with storage, and really any technology? We find that they are not perfect, that they do fail. In fact, we can just rely on the fact that technology is going to fail at some point in time, so we need to plan accordingly. We need to make sure that if we have mission critical data, we have access to it even after a failure. That is one thing that redundancy provides us.
This is a hard disk drive right here, and this disk drive has moving parts to it. The disk spins, it has got a drive that spins the media, and we have got a little arm that swings down and reads that data. We find that these things are prone to die over time. There are actual bearings in there, and those bearings wear out, so this hard drive can seize up and we could lose all of our data.
I know friends who have lost huge amounts of data, and I know businesses that have lost huge amounts of data, and this can be a real problem if we are relying on that data and we have invested so much time in acquiring or creating it. So we need solutions to guard against failures: failures of our devices, failures of our data, and loss of the data.
Redundancy is one of the solutions for that. Redundancy is an extra component that we can utilize to help make sure that if one of these components dies, we have an extra one involved. That is what is called redundancy, and it is one of those things that helps give us availability.
Think of a spare tire on a car. If you have a car that has four tires but it also has a spare, then if you get a flat on any one of those four tires you can replace it with the spare. That is what redundancy is.
If we have data, we have got to think about how we create redundant data, as well as, if that data is being hosted in the cloud or on our different devices, other aspects of redundancy. If we are hosting out this data, we may need to duplicate our hardware and software, or our internet and networking, or cooling and power. Maybe we even need to distribute it across different locations, so if there is an earthquake or some sort of disaster that happens in one area, we can pick it up in another area of the country, or even the world.
One of the most common data redundancies that we have is that we just duplicate whatever devices or drives we have. In this case right here, this is a hard disk drive, so perhaps I do what is called mirroring, and create a whole other drive that has a copy of the same data on both drives.
There are many ways that we can create redundancy within our drives. One example of that is RAID. RAID is a way that we can use multiple disks in order to save our data, and depending on what we are trying to achieve there are different levels of RAID. I am not going to get real in depth into that, but one example of this is disk mirroring. We can use RAID, and there is software RAID and hardware RAID, but what we can do is mirror the image of a disk, so any data gets copied to two different disks. Any one of these disks could die and we still have our data, and it can still be up and running.
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