In reality, most hard disks seldom see operating temperatures below the chill of a server room or beyond the warmth of rack space, and most disks will not commit an URE that crashes a RAID-5 rebuild. While it is agreed that better parity schemes exist, the exception is not the rule. My customer could have retained cold storage data to individual disks via removable drives, with no redundancy at all. In fact, most organizations already use a single removable disk or cloud container for their nightly backup routine. My customer choose a special backup appliance that fits three disks into a single cartridge, further protecting archived data and proving RAID-5 still has business applications.
As the size of information stored in the cloud grows increasingly larger, IT managers must plan on getting data out of the cloud when it’s critically needed during disaster recovery. For some businesses, the cloud is a place to deposit a second copy of data already retained locally. For others the cloud is primary storage, where unique data is created and modified. Problems arise in both cases: when local data is lost due to fire, flood, or theft, when the data is too large for a timely transfer across limited Internet bandwidth, or when a cloud provider shuts down. This all begs the question: is redundant data in place?