Method for managing backup data, electronic device and computer program product

1. A method of managing backup data, comprising:

obtaining historical information of a plurality of historical operations on target data in a backup storage device during a first time period, the historical information indicating at least types and time of occurrences of the plurality of historical operations, wherein the historical information is stored in a memory as a historical information list that includes a hash value of the target data, a type of a historical operation, from the plurality of historical operations, on the target data and a time of an occurrence of the historical operation;

determining, based on the historical information, a first time interval between time of occurrences of adjacent deletion operations within the first time period at which the target data has been deleted;

determining whether the target data is to be rewritten to the backup storage device within a second time period after the first time period based on the first time interval;

in response to determining that the target data is to be written to the backup storage device within the second time period, determining whether the target data has been deleted from the backup storage device due to expiration, wherein the deleted target data is stored as historical backup data;

in response to determining that the target data has been deleted from the backup storage device due to expiration, rewriting the target data, from the historical backup data, to the backup storage device based on a request to write the target data; and

adjusting an expiration time of the target data in the backup storage device, wherein adjusting the expiration time further comprises:

computing a plurality of second time intervals between a plurality of write operations of the target data within the first time period based on the historical information;

determining a third time interval from the plurality of second time intervals based on a degree of change in time between two adjacent second time intervals in the plurality of second time intervals; and

adjusting the expiration time of the target data in the backup storage device based on the third time interval.

2. The method of claim 1 , wherein obtaining the historical information comprises:

in response to the historical operation on the target data during the first time period, determining the hash value of the target data; and

storing the type and the time of the occurrence of the historical operation in association with the hash value.

3. The method of claim 1 , wherein determining whether the target data is to be rewritten to the backup storage device within the second time period comprises:

determining a metric for the target data based on the historical information, the metric comprising the first time interval; and

determining, based on the metric, whether the target data is to be rewritten to the backup storage device within the second time period.

4. The method of claim 3 , wherein determining, based on the metric, whether the target data is to be written to the backup storage device within the second time period comprises:

processing the metric with a machine learning model to determine whether the target data is to be written to the backup storage device within the second time period, wherein the machine learning model is trained based on at least one of: a reference metric determined based on a plurality of historical operations on reference data during a third time period, and an indication of whether the reference data are written to the backup storage device within a fourth time period after the third time period.

5. The method of claim 1 , further comprising:

determining an average time interval of the plurality of second time intervals, wherein each one of the plurality of second time intervals is an amount of time between two adjacent write operations from the plurality of write operations;

filtering out one or more second time interval pairs from the plurality of second time intervals whose difference in time is greater than the average time interval to produce a filtered plurality of second time intervals; and

determining the third time interval based on the filtered plurality of second time intervals.

6. An electronic device, comprising:

at least one processing unit;

at least one memory coupled to the at least one processing unit and storing instructions executable by the at least one processing unit, the instructions, when executed by the at least one processing unit, causing the device to perform acts comprising:

obtaining historical information of a plurality of historical operations on target data in a backup storage device during a first time period, the historical information indicating at least types and time of occurrences of the plurality of historical operations, wherein the historical information is stored in a memory as a historical information list that includes a hash value of the target data, a type of a historical operation, from the plurality of historical operations, on the target data and a time of an occurrence of the historical operation;

determining, based on the historical information, a first time interval between time of occurrences of adjacent deletion operations within the first time period at which the target data has been deleted;

determining whether the target data is to be rewritten to the backup storage device within a second time period after the first time period based on the first time interval;

in response to determining that the target data is to be written to the backup storage device within the second time period, determining whether the target data has been deleted from the backup storage device due to expiration, wherein the deleted target data is stored as historical backup data;

in response to determining that the target data has been deleted from the backup storage device due to expiration, rewriting the target data, from the historical backup data, to the backup storage device based on a request to write the target data; and

adjusting an expiration time of the target data in the backup storage device, wherein adjusting the expiration time further comprises:

computing a plurality of second time intervals between a plurality of write operations of the target data within the first time period based on the historical information;

determining a third time interval from the plurality of second time intervals based on a degree of change in time between two adjacent second time intervals in the plurality of second time intervals; and

adjusting the expiration time of the target data in the backup storage device based on the third time interval.

7. The device of claim 6 , wherein obtaining the historical information comprises:

in response to the historical operation on the target data during the first time period, determining the hash value of the target data; and

storing the type and the time of the occurrence of the historical operation in association with the hash value.

8. The device of claim 6 , wherein determining whether the target data is to be rewritten to the backup storage device within the second time period comprises:

determining a metric for the target data based on the historical information, the metric comprising the first time interval; and

determining, based on the metric, whether the target data is to be rewritten to the backup storage device within the second time period.

9. The device of claim 8 , wherein determining, based on the metric, whether the target data is to be written to the backup storage device within the second time period comprises:

processing the metric with a machine learning model to determine whether the target data is to be written to the backup storage device within the second time period, wherein the machine learning model is trained based on at least one of: a reference metric determined based on a plurality of historical operations on reference data during a third time period, and an indication of whether the reference data are written to the backup storage device within a fourth time period after the third time period.

10. The device of claim 6 , wherein the instructions cause the device to perform further acts comprising:

determining an average time interval of the plurality of second time intervals, wherein each one of the plurality of second time intervals is an amount of time between two adjacent write operations from the plurality of write operations;

filtering out one or more second time interval pairs from the plurality of second time intervals whose difference in time is greater than the average time interval to produce a filtered plurality of second time intervals; and

determining the third time interval based on the filtered plurality of second time intervals.

11. A computer program product being tangibly stored on a non-transitory computer readable medium and comprising machine-executable instructions which, when executed in a device, cause the device to perform operations, the operations comprising:

obtaining historical information of a plurality of historical operations on target data in a backup storage device during a first time period, the historical information indicating at least types and time of occurrences of the plurality of historical operations, wherein the historical information is stored in a memory as a historical information list that includes a hash value of the target data, a type of a historical operation, from the plurality of historical operations, on the target data and a time of an occurrence of the historical operation;

determining, based on the historical information, a first time interval between time of occurrences of adjacent deletion operations within the first time period at which the target data has been deleted;

determining whether the target data is to be rewritten to the backup storage device within a second time period after the first time period based on the first time interval;

in response to determining that the target data is to be written to the backup storage device within the second time period, determining whether the target data has been deleted from the backup storage device due to expiration, wherein the deleted target data is stored as historical backup data;

in response to determining that the target data has been deleted from the backup storage device due to expiration, rewriting the target data, from the historical backup data, to the backup storage device based on a request to write the target data; and

adjusting an expiration time of the target data in the backup storage device, wherein adjusting the expiration time further comprises:

computing a plurality of second time intervals between a plurality of write operations of the target data within the first time period based on the historical information;

determining a third time interval from the plurality of second time intervals based on a degree of change in time between two adjacent second time intervals in the plurality of second time intervals; and

adjusting the expiration time of the target data in the backup storage device based on the third time interval.

12. The computer program product of claim 11 , wherein obtaining the historical information comprises:

in response to the historical operation on the target data during the first time period, determining the hash value of the target data; and

storing the type and the time of the occurrence of the historical operation in association with the hash value.

13. The computer program product of claim 11 , wherein determining whether the target data is to be rewritten to the backup storage device within the second time period comprises:

determining a metric for the target data based on the historical information, the metric comprising the first time interval; and

determining, based on the metric, whether the target data is to be rewritten to the backup storage device within the second time period.

14. The computer program product of claim 13 , wherein determining, based on the metric, whether the target data is to be written to the backup storage device within the second time period comprises:

processing the metric with a machine learning model to determine whether the target data is to be written to the backup storage device within the second time period, wherein the machine learning model is trained based on at least one of: a reference metric determined based on a plurality of historical operations on reference data during a third time period, and an indication of whether the reference data are written to the backup storage device within a fourth time period after the third time period.

15. The computer program product of claim 11 , wherein the machine-executable instructions cause the device to perform further operations comprising:

determining an average time interval of the plurality of second time intervals, wherein each one of the plurality of second time intervals is an amount of time between two adjacent write operations from the plurality of write operations;

filtering out one or more second time interval pairs from the plurality of second time intervals whose difference in time is greater than the average time interval to produce a filtered plurality of second time intervals; and

determining the third time interval based on the filtered plurality of second time intervals.