Systems and methods for efficient storage access using metadata

Patent metadata

Field	Value
Publication number	US-9710514-B1
Application number	US-201414314396-A
Country	US
Kind code	B1
Filing date	Jun 25, 2014
Priority date	Jun 25, 2013
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

Systems and methods are provided for using metadata to efficiently access object data from two or more storage components. Control circuitry receives a request from a host device to perform an operation on a uniquely identified object in a storage system comprising at least a first storage component and a second storage component. Control circuitry retrieves metadata information about the location of the object in store, wherein the metadata information comprises a first indication of a location of the object in the first storage component and a second indication of a location of the object in the second storage component. The objects in one or both of the first and second storage components are located based on the retrieved metadata information, and the requested operation is performed on the requested object.

First claim

What is claimed is:

1. A method for accessing information from storage, the method comprising:
receiving, using control circuitry, a request to perform an operation on a uniquely identified object located in storage, wherein the storage comprises a first storage component and a second storage component, wherein the first storage component stores a reverse lookup hash table, wherein each entry of the reverse lookup hash table identifies which entry in a metadata hash table identifies a storage location of each object in the first storage component;
in response to receiving the request, retrieving, using the control circuitry, from the metadata hash table stored in the first storage component metadata information about one or more locations of the object in storage, wherein the retrieved metadata information comprises a first indication of the location of the object in the first storage component and a second indication of a location of the object in the second storage component;
locating the object in storage based on the first indication and the second indication of the retrieved metadata information; and
performing the operation on the located object.

2. The method of claim 1 , wherein the retrieved metadata information indicates that the object is located in both the first storage component and the second storage component.

3. The method of claim 1 , wherein objects stored in the first storage component are accessed more quickly than objects stored in the second storage component.

4. The method of claim 1 , wherein:
the first indication points to a logical memory block corresponding to a physical location of the object in the first storage component, and
the second indication points to a logical memory block corresponding to a physical location of the object in the second storage component.

5. The method of claim 1 , wherein the retrieved metadata information is a first entry retrieved from a plurality of entries in the metadata hash table, wherein each of the plurality of entries is associated with a different uniquely identified object.

6. The method of claim 5 , wherein the first entry in the metadata hash table maps the object to the first indication of the location of the object in the first storage component; and
a first entry in the reverse lookup hash table maps the first indication of the location of the object in the first storage component to the first entry in the metadata hash table.

7. The method of claim 5 , wherein each entry in the metadata hash table contains information about a current state of the object, wherein the current state is used to determine which operations are permissible to be performed on the object.

8. The method of claim 5 , wherein each entry in the metadata hash table contains a counter that indicates a number of times an operation associated with the object has been requested.

9. The method of claim 5 , wherein each entry of the metadata hash table is associated with a respective lock, further comprising:
in response to determining that the object is already locked by the lock associated with the first entry, delaying performance of the requested operation on the object until the first entry is no longer locked; and
performing an operation on another uniquely identified object associated with a second entry in the metadata hash table, wherein the operation is performed while the first entry is locked and the second entry is not locked.

10. The method of claim 5 , wherein:
the second storage component stores a second reverse lookup hash table, wherein each entry of the second reverse lookup hash table indicates that the location of the object in the second storage component is associated with the respective entry of the metadata hash table.

11. An apparatus for accessing information from storage, the apparatus comprising:
control circuitry configured to:
receive, from a host device, a request to perform an operation on a uniquely identified object located in storage, wherein the storage comprises a first storage component and a second storage component, wherein the first storage component stores a reverse lookup hash table, wherein each entry of the reverse lookup hash table identifies which entry in a metadata hash table identifies a storage location of each object in the first storage component;
in response to receiving the request, retrieve from the metadata hash table stored in the first storage component metadata information about one or more locations of the object in storage, wherein the retrieved metadata information comprises a first indication of a location of the object in the first storage component and a second indication of a location of the object in the second storage component; and
storage component circuitry configured to:
locate the object in storage based on the first indication and the second indication of the retrieved metadata information; and
perform the operation on the located object.

12. The apparatus of claim 11 , wherein the retrieved metadata information indicates that the object is located in both the first storage component and the second storage component.

13. The apparatus of claim 11 , wherein objects stored in the first storage component are accessed more quickly than objects stored in the second storage component.

14. The apparatus of claim 11 , wherein:
the first indication points to a logical memory block corresponding to a physical location of the object in the first storage component, and
the second indication points to a logical memory block corresponding to a physical location of the object in the second storage component.

15. The apparatus of claim 11 , wherein the retrieved metadata information is a first entry retrieved from a plurality of entries in the metadata hash table, wherein each of the plurality of entries is associated with a different uniquely identified object.

16. The apparatus of claim 15 , wherein the first entry in the metadata hash table maps the object to the first indication of the location of the object in the first storage component; and
a first entry in the reverse lookup hash table maps the first indication of the location of the object in the first storage component to the first entry in the metadata hash table.

17. The apparatus of claim 15 , wherein each entry in the metadata hash table contains information about a current state of the object, wherein the current state is used to determine which operations are permissible to be performed on the object.

18. The apparatus of claim 15 , wherein each entry in the metadata hash table contains a counter that indicates a number of times an operation associated with the object has been requested.

19. The apparatus of claim 15 , wherein each entry of the metadata hash table is associated with a respective lock and wherein the control circuitry is further configured to:
in response to determining that the object is already locked by the lock associated with the first entry, delay performance of the requested operation on the object until the first entry is no longer locked; and
perform an operation on another uniquely identified object associated with a second entry in the metadata hash table, wherein the operation is performed while the first entry is locked and the second entry is not locked.

20. The apparatus of claim 15 , wherein:
the second storage component stores a second reverse lookup hash table, wherein each entry of the second reverse lookup hash table indicates that the location of the requested object in the second storage compone

Assignees

• Marvell Int Ltd

Inventors

• Gole Abhijeet P
• Johri Ram Kishore

Classifications

• G06F17/30424 Primary

  Physics · mapped topic

• G06F17/30949

  Physics · mapped topic

• G06F17/30091

  Physics · mapped topic

• G06F16/137 Primary

  Hash-based (content-based indexing of textual data G06F16/31) · CPC title

• G06F16/245 Primary

  Query processing · CPC title