Measurement of Object Stores Measurement of Object Stores Recovery management in database systems provides engineering solutions to failure, offering a required degree of reliability by automatically restoring a system to a coherent and acceptable state. Conceptually the user manipulates data through reads and writes to a database implemented on non-volatile storage, with volatile storage being used as a cache.
Recovery is required because by definition volatile cache contents are lost when the system crashes.
When failure occurs the user should not be left with an inconsistent state in the non-volatile store. Recovery mechanisms prevent this by controlling the writes to non-volatile storage so that some high level abstraction of atomicity is maintained. Hence many recovery mechanisms have been invented, each with different performance tradeoffs. Each technique's costs involves not only the overhead of restoring data after failures but also the time and space overhead required to maintain sufficient recovery information during normal operation to ensure recovery. Under different workloads and configurations these crash recovery mechanisms exhibit different costs.