Understanding block storage: Local and SAN
At the root of any standard storage mechanism that we will encounter today is the concept of block devices. Block devices are storage devices that allow for non-volatile data storage that can be stored and retrieved in arbitrary order. In a practical sense, think of the standard block device as being the hard drive. Hard drives are the prototypical block device, and we can think of any other block device as behaving like a hard drive. We can also refer to this as implementing a drive interface or appearance.
Many things are block devices. Traditional spinning hard drives, solid state drives (SSD), floppy disks, CD-ROM, DVD-ROM, tape drives, RAM disks, RAID arrays and more are all block devices. As far as a computer is concerned, all of these devices are the same. This makes things simple as a system administrator: everything is built on block devices.
From a system administrator perspective, we often simple refer to block devices as...