| 摘要 |
In a computerized data storage system, when data is to be updated in a primary, or "base," logical volume, a snapshot volume is formed from the base volume. The updates are then made to the snapshot volume, preferably while the base volume is still used to satisfy normal I/O (input/output) access requests. After the updating is complete, the snapshot volume is rolled back into the base volume. During the rollback, any remaining original data in the base volume and the updated data in either the base volume or snapshot volume are available for satisfying the normal I/O access requests. Thus, the updating appears to be instantaneous, since the entire updated data is immediately available upon starting the rollback.
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