The time that it takes a storage system to rebuild data from a failed disk drive is crucial to the data reliability of that system. With the advent of multi-terabyte drives, and the creation of increasingly larger single volumes and file systems, typical recovery times for large, multi-terabyte SATA drive failures are becoming multiple days or even weeks. During this MTTDL period, storage systems are vulnerable to additional drive failures and the resulting data loss and downtime.
Since OneFS is built upon a highly distributed architecture, it is able to use the CPU, memory, and spindles from multiple nodes to reconstruct data from failed drives in a highly parallel and efficient manner. Because a cluster is not bound by the speed of any particular drive, OneFS is able to recover from drive failures extremely quickly and this efficiency grows relative to cluster size. As such, a failed drive within a cluster will be rebuilt an order of magnitude faster than hardware RAID-based storage devices. Also, OneFS has no requirement for dedicated hot spare drives.