| 摘要 |
A data storage system ( 100 ) and a method of storing data are described including a cache ( 118 ) with a variable number of levels ( 210, 220, 230, 240 ). Each level in the cache ( 118 ) has a cache controller ( 212, 222, 232, 242 ) and a cache memory ( 214, 224, 234, 244 ) for storing data. An address mapping is recorded and applied between each of the levels of the cache ( 118 ). The address mapping corresponds to a point in time virtual copy operation such as a snapshot copy operation applied to the cache ( 118 ) and enables point in time virtual copy operations to be carried out in electronic time. A new level is created in the cache ( 118 ) when a point in time virtual copy operation is received by the cache and a corresponding address mapping is applied to the previous level in the cache ( 118 ).
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