| 摘要 |
In one aspect of the present description, a data preservation function is provided for preserving a set of data on a source storage device at a point in time, and includes identifying as a function of prior update usage, such as input/output usage, of the data to be preserved, a portion of the data which is more likely to be the subject of updates during at least a portion of the data preservation operation as compared to the remaining portion of the data to be preserved, and copies the identified portion of the data to be preserved to a target storage device. In another aspect, the size of the portion of data to be identified is variable. In one embodiment, the size of the portion of data to be identified is a function of a parameter of the command, such that a user can specify the command parameter which affects the size of the portion of data which is prewritten to the target storage device. The parameter may be, for example, a percentage of the data to be preserved, such that a user can specify the percentage of the point-in-time data which is prewritten to the target storage device. Alternatively, the parameter may be, for example, a probability of a collision occurring, such that a user can specify a probability of a collision occurring. Other features and aspects may be realized, depending upon the particular application.
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