RAID Unbound: Storage Fault Tolerance in a Distributed Environment
Mirroring, data replication, backup, and more recently, redundant arrays of independent disks (RAID) are all technologies used to protect and ensure access to critical company data. A new set of problems has arisen as data becomes more and more geographically distributed. Each of the technologies listed above provides important benefits; but each has failed to adapt fully to the realities of distributed computing. The key to data high availability and protection is to take the technologies' strengths and 'virtualize' them across a distributed network. RAID and mirroring offer high data availability, which data replication and backup provide strong data protection. If we take these concepts at a very granular level (defining user, record, block, file, or directory types) and them liberate them from the physical subsystems with which they have traditionally been associated, we have the opportunity to create a highly scalable network wide storage fault tolerance. The network becomes the virtual storage space in which the traditional concepts of data high availability and protection are implemented without their corresponding physical constraints.