Storage system with multicast DMA and unified address space
A system and method for clients, a control module, and storage modules to participate in a unifed address space in order to and read and write data efficiently using direct-memory access. The method for reading data includes determining a first location in a first memory to write a first copy of the data, a second location in a second memory to write a second copy of the data, where the first memory is located in a first storage module including a first persistent storage and the second memory is located in a second storage module including a second persistent storage. The method further includes programming a direct memory access engine to read the data from the client memory and issue a first write request to a multicast address, where the first location, the second location, and a third location are associated with the multicast address.
1. A method for writing data, comprising:
receiving, from a client, a request to write data, wherein the data is located in client memory;
selecting, by a storage appliance, a first location in a first memory to write a first copy of the data, a second location in a second memory to write a second copy of the data, wherein the first memory is located in a first storage module comprising a first persistent storage and the second memory is located in a second storage module comprising a second persistent storage, wherein the storage appliance comprises the first storage module and the second storage module;
after the selecting:
obtaining the data by the storage appliance;
in response to obtaining the data, generating a first request to write the first copy to the first location, a second request to write the second copy to the second location, and a third request to write a third copy to a third location, wherein the third location is in a third memory in a control module in the storage appliance;
wherein the first copy of the data is written to the first location in response to the first request,
wherein the second copy of the data is written to the second location in response to the second request, and
wherein the third copy of the data is written to the third location in response to the third request.
2. The method of claim 1 , further comprising:
after the first copy of the data is written to the first location, the second copy of the data is written to the second location, and the third copy of the data is written to the third location:
notifying the client that the request to write the data was completed.
3. The method of claim 2 , further comprising:
after notifying the client:
writing the first copy of the data to the first persistent storage.
4. The method of claim 3 , wherein a processor in the storage appliance initiates writing of the first copy of the data to the first persistent storage.
5. The method of claim 1 , wherein the first persistent storage comprises a solid state memory module.
6. The method of claim 5 , wherein the solid state memory module comprises a plurality of NAND dies.
7. The method of claim 1 , wherein the first memory, the second memory, the third memory, and at least a portion of the client memory are part of a unified address space.
8. A storage appliance, comprising:
a first storage module comprising a first memory and a first persistent storage; and
a second storage module comprising a second memory and a second persistent storage;
a control module comprising:
a processor, and
a third memory,
wherein the control module is configured to:
receive, from a client, a first request to write data, wherein the data is located in client memory;
select a first location in the first memory to write a first copy of the data and select a second location in the second memory to write a second copy of the data;
after selecting the first location, after selecting the second location, and after obtaining the data by the storage appliance from the client:
generate a second request to write the first copy of the data to the first location, a third request to write the second copy of the data to the second location, and a fourth request to write a third copy of the data to a third location in the third memory;
wherein the first storage module is configured to, in response to the second request, store the first copy of the data in the first location;
wherein the second storage module is configured to, in response to the third request, store the second copy of the data in the second location; and
wherein, in response to the fourth request, the third copy of the data is stored in the third location.
9. The storage appliance of claim 8 , wherein the control module is further configured to:
after the first copy of the data is written to the first location, the second copy of the data is written to the second location, and the third copy of the data is written to the third location:
notify the client that the request to write the data was completed.
10. The storage appliance of claim 9 , wherein the control module is further configured to:
after notifying the client:
write the first copy of the data to the first persistent storage.
11. The storage appliance of claim 8 , wherein the first memory is vaulted memory.
12. The storage appliance of claim 8 , wherein the first persistent storage comprises solid state memory.
13. The storage appliance of claim 8 , wherein the first persistent storage comprises NAND flash.
14. The storage appliance of claim 8 , wherein the first memory, the second memory, the third memory, and at least a portion of the client memory are part of a storage fabric.
15. The storage appliance of claim 14 , wherein the stored fabric is associated with a unified address space.