Multivariate data backup retention policies

1. A method comprising:

generating a snapshot of a dataset stored in a storage system by applying different retention policies to different portions of the dataset within the snapshot, including associating a first subset of the dataset within the snapshot with a first retention policy within the snapshot and a second subset of the dataset within the snapshot with a second retention policy;

generating tracking information indicating the respective subsets of the dataset corresponding to the respective retention policies of a plurality of retention policies; and

based on the tracking information, invalidating, by the storage system, the first subset of the dataset from the snapshot based on the first retention policy while retaining the second subset of the dataset within the snapshot based on the second retention policy.

2. The method of claim 1 , further comprising:

deleting, after lapse of a first time period and based on a first retention policy corresponding to a first subset of the subsets of the dataset, the first subset; and

retaining, after lapse of the first time period and based on a second retention policy corresponding to a second subset of the subsets of the dataset, the second sub set.

3. The method of claim 2 , wherein the dataset is a volume of data, and wherein deleting the first subset comprises:

mounting the volume of data to extract the second subset prior to deleting the snapshot.

4. The method of claim 2 , wherein retaining the second subset includes generating tracking information for the second subset that includes generating a reference to one or more portions of storage content managed by a deduplication process.

5. The method of claim 1 , wherein a file system includes tracking information for each of the portions of the dataset, and wherein the tracking information is used to determine retention of the subsets in accordance with the plurality of retention policies.

6. The method of claim 1 , wherein the plurality of retention policies includes policies based on one or more of: user designation of one or more files, ownership of a file, priority level of a file, priority level of an application or system process that created a file, content of a data object, a tag or attribute associated with the data object, a file type, a specified directory, or read or write privileges of a file or directory.

7. The method of claim 1 , wherein for a length of time corresponding to a given retention policy for a given portion of the dataset, a version history is updated to indicate availability of any retained subsets of data as additional snapshots are taken.

8. An apparatus comprising a computer processor, a computer memory operatively coupled to the computer processor, the computer memory having disposed within it computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of:

generating a snapshot of a dataset stored in a storage system by applying different retention policies to different portions of the dataset within the snapshot, including associating a first subset of the dataset within the snapshot with a first retention policy within the snapshot and a second subset of the dataset within the snapshot with a second retention policy;

generating tracking information indicating the respective subsets of the dataset corresponding to the respective retention policies of a plurality of retention policies; and

based on the tracking information, invalidating, by the storage system, the first subset of the dataset from the snapshot based on the first retention policy while retaining the second subset of the dataset within the snapshot based on the second retention policy.

9. The apparatus of claim 8 , further comprising computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of:

deleting, after lapse of a first time period and based on a first retention policy corresponding to a first subset of the subsets of the dataset, the first subset; and

retaining, after lapse of the first time period and based on a second retention policy corresponding to a second subset of the subsets of the dataset, the second sub set.

10. The apparatus of claim 9 , wherein the dataset is a volume of data, and wherein deleting the first subset includes:

mounting the volume of data to extract the second subset prior to deleting the snapshot.

11. The apparatus of claim 9 , wherein retaining the second subset includes generating tracking information for the second subset that includes generating a reference to one or more portions of storage content managed by a deduplication process.

12. The apparatus of claim 8 , wherein a file system includes tracking information for each of the subsets of the dataset, and wherein the tracking information is used to determine retention of the subsets in accordance with the plurality of retention policies.

13. The apparatus of claim 8 , wherein the plurality of retention policies includes policies based on one or more of: user designation of one or more files, ownership of a file, priority level of a file, priority level of an application or system process that created a file, a file type, a specified directory, or read or write privileges of a file or directory.

14. The apparatus of claim 8 , wherein for a length of time corresponding to a given retention policy for a given portion of the dataset, a version history is updated to indicate availability of any retained subsets of data as additional snapshots are taken.

15. A computer program product disposed upon a non-transitory computer readable medium, the computer program product comprising computer program instructions that, when executed, cause a computer to carry out the steps of:

generating a snapshot of a dataset stored in a storage system by applying different retention policies to different portions of the dataset within the snapshot, including associating a first subset of the dataset within the snapshot with a first retention policy within the snapshot and a second subset of the dataset within the snapshot with a second retention policy;

generating tracking information indicating the respective subsets of the dataset corresponding to the respective retention policies of a plurality of retention policies; and

based on the tracking information, invalidating, by the storage system, the first subset of the dataset from the snapshot based on the first retention policy while retaining the second subset of the dataset within the snapshot based on the second retention policy.

16. The computer program product of claim 15 , further comprising computer program instructions that, when executed, cause the computer to carry out the steps of:

deleting, after lapse of a first time period and based on a first retention policy corresponding to a first subset of the subsets of the dataset, the first subset; and

retaining, after lapse of the first time period and based on a second retention policy corresponding to a second subset of the subsets of the dataset, the second sub set.

17. The computer program product of claim 16 , wherein the dataset is a volume of data, and wherein deleting the first subset comprises:

mounting the volume of data to extract the second subset prior to deleting the snapshot.

18. The computer program product of claim 16 , wherein retaining the second subset includes generating tracking information for the second subset that includes generating a reference to one or more portions of storage content managed by a deduplication process.

19. The computer program product of claim 15 , wherein a file system includes tracking information for each of the subsets of the dataset, and wherein the tracking information is used to determine retention of the subsets in accordance with the plurality of retention policies.

20. The computer program product of claim 15 , wherein the plurality of retention policies includes policies based on one or more of: user designation of one or more files, ownership of a file, priority level of a file, priority level of an application or system process that created a file, a file type, a specified directory, or read or write privileges of a file or directory.