Determining storage consumption in a storage system

1. A method comprising:

for a group of data units within a storage system storing a plurality of client entities:

for each data unit in the group of data units, determining whether the data unit is reachable by one of the plurality of client entities; and

for each data unit reachable by one of the plurality of client entities, determining a category for the data unit;

calculating storage consumption for a client based on the category of each data unit reachable by one of the plurality of client entities; and

reporting the calculated storage consumption.

2. The method of claim 1 , wherein calculating storage consumption for the client based on the category of each data unit reachable by one of the plurality of client entities comprises applying an accounting policy to assign units of storage consumption based on the category of each data unit reachable by one of the plurality of client entities.

3. The method of claim 1 , wherein determining the category for the data unit comprises determining a type of client entity utilizing the data unit.

4. The method of claim 1 , wherein determining whether the data unit is reachable by one of the plurality of client entities comprises iterating over a database graph organizing the group of data units.

5. The method of claim 1 , wherein the group of data units comprises data units from at least two storage arrays in the storage system.

6. The method of claim 1 , wherein the plurality of client entities include at least one volume and at least one snapshot.

7. The method of claim 1 , wherein the data units are one of a data block, an extent, and a segment.

8. The method of claim 1 , wherein calculating storage consumption for the client based on the category of each data unit reachable by one of the plurality of client entities comprises assigning units of storage consumption based on a number of times each data unit is shared between client entities.

9. The method of claim 1 , wherein calculating storage consumption for the client based on the category of each data unit reachable by one of the plurality of client entities comprises accounting for compression.

10. The method of claim 1 , wherein calculating storage consumption for the client based on the category of each data unit reachable by one of the plurality of client entities comprises accounting for snapshots.

11. The method of claim 1 , wherein calculating storage consumption for the client based on the category of each data unit reachable by one of the plurality of client entities comprises accounting for deduplication.

12. A storage system 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 storage system to carry out the steps of:

scanning a group of low-level data units within the storage system storing a plurality of client entities, including:

for each data unit in the group of low-level data units, determining whether the data unit is reachable by one of the plurality of client entities; and

for each data unit reachable by one of the plurality of client entities, determining a category for the data unit;

calculating storage consumption for a client based on the category of each data unit reachable by one of the plurality of client entities; and

reporting the calculated storage consumption.

13. The storage system of claim 12 , wherein calculating storage consumption for the client based on the category of each data unit reachable by one of the plurality of client entities comprises applying an accounting policy to assign units of storage consumption based on the category of each data unit reachable by one of the plurality of client entities.

14. The storage system of claim 12 , wherein determining the category for the data unit comprises determining a type of client entity utilizing the data unit.

15. The storage system of claim 12 , wherein scanning the group of low-level data units within the storage system comprises iterating over a database graph organizing the group of low-level data units.

16. The storage system of claim 12 , wherein the group of low-level data units comprises data units from at least two storage arrays in the storage system.

17. The storage system of claim 12 , wherein the plurality of client entities include at least one volume and at least one snapshot.

18. The storage system of claim 12 , wherein the data units are one of a data block, an extent, and a segment.

19. The storage system of claim 12 , wherein calculating storage consumption for the client based on the category of each data unit reachable by one of the plurality of client entities comprises assigning units of storage consumption based on a number of times each data unit is shared between client entities.

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

scanning a group of data units within a storage system storing a plurality of client entities, including:

for each data unit in the group of data units, determining whether the data unit is reachable by one of the plurality of client entities; and

for each data unit reachable by one of the plurality of client entities, determining a category for the data unit;

calculating storage consumption for a client based on the category of each data unit reachable by one of the plurality of client entities; and

reporting the calculated storage consumption.