Content addressable storage with reduced latency

1. A storage system, comprising:

a content-addressable storage system and a persistent cache, wherein the persistent cache comprises:

a non-volatile memory;

a temporary address generator configured to generate a temporary address which is associated with data to be stored in the persistent cache in response to a write request from an application;

a non-content-addressable storage system configured to store and retrieve data in the persistent cache using the temporary address;

a cache manager configured to forward a write acknowledgment comprising the temporary address to the application and write the data that was stored in the non-content-addressable storage system to the content-addressable storage system; and

an address translator configured to map a temporary address associated with the data in the non-content addressable storage system with a content address associated with the data in the content-addressable storage system;

wherein the application initially request the data using the temporary address and subsequently requests the data using the content address, and wherein the cache manager issues a read request to either the non-content-addressable storage system or the content-addressable storage system depending upon whether an address received from the application is determined to be the temporary address or the content address based on a bit in the address.

2. The system of claim 1 , wherein the cache manager is further configured to determine whether an address associated with a read request is the temporary address or the content address.

3. The system of claim 1 , wherein the persistent cache handles a read request for the temporary address by reading data associated with the temporary address from the persistent cache if the data resides in the non-content-addressable storage system, or alternatively by obtaining from the address translator the content address associated with the temporary address and issuing a read request to the content-addressable storage system using the content address.

4. The system of claim 1 , wherein data is deleted from the persistent cache after the data has been written to the content-addressable storage system, but the mapping between the temporary address and the content address is retained.

5. The system of claim 1 , wherein a mapping between the temporary address and the content address is periodically deleted.

6. The system of claim 5 , wherein the mapping is deleted after an application drops all temporary addresses returned to it.

7. The system of claim 1 , wherein the non-content addressable storage system comprises a solid-state drive or hard disk drive.

8. A method for storing data in a storage system, comprising:

determining whether data associated with a write request issued by an application is to be stored in a non-content-addressable storage system or written directly to a content-addressable storage system;

if it is determined that the data is to be stored in the non-content-addressable storage system:

generating a temporary address for the data to be stored in the non-content-addressable storage system;

issuing an acknowledgment to the application that data is persistently stored in the non-content addressable storage system before the data is written to a content-addressable storage system, the acknowledgment including the temporary address;

writing the data that was stored in the non-content-addressable storage system to the content-addressable storage system; and

mapping at least one temporary address associated with the data in the non-content-addressable storage system with a content address of the data in the content-addressable storage system after the data is written to the content-addressable storage system;

wherein the application initially requests the data using the temporary address and subsequently requests the data using the content address, and wherein a cache manager issues a read request to either the non-content-addressable storage system or the content-addressable storage system depending upon whether an address received from the application is determined to be the temporary address or the content address based on a bit in the address.

9. The method of claim 8 , wherein the storage system is configured to determine whether an address associated with a read request is the temporary address or the content address.

10. The method of claim 8 , wherein a read request for the temporary address is handled by reading data associated with the temporary address from the non-content addressable storage system if the data resides in the non-content-addressable storage system, or alternatively by obtaining the content address associated with the temporary address and issuing a read request to the content-addressable storage system using the content address.

11. The method of claim 8 , wherein data is deleted from the non-content-addressable storage system after the data has been written to the content-addressable storage system, but the mapping between the temporary address and the content address is retained.

12. The method of claim 8 , wherein a mapping between the temporary address and the content address is periodically deleted.

13. The method of claim 12 , wherein the mapping is deleted after an application drops all temporary addresses returned to it.

14. The method of claim 8 , wherein the non-content addressable storage system comprises a solid-state drive or hard disk drive.