METHOD AND APPARATUS FOR DATA ACCESS IN STORAGE SYSTEM
Embodiments of the present disclosure provide a method and apparatus for data access in a storage system. The solution divides local cache of each of the plurality of controllers in the storage system into dedicated area and shared area, wherein the shared area is uniformly addressed to form a global shared address space. Accordingly, a controller can access and utilize local cache that originally belongs to other controllers, so as to improve cache utilization rate of the storage system. The plurality of controllers in the storage system has a high-speed communication interface therebetween. The solution of the present disclosure enables a controller to utilize cache resources of other controllers in the storage system, so as to achieve the purpose of coordinating cache resources in the storage system.
1 . A method for data access in a storage system, the method comprising:
receiving, from a controller among a plurality of controllers in the storage system, an access request for data, the plurality of controllers having respective local caches;
determining whether the data is located in a dedicated area of the local cache of the controller;
in response to the data being missed in the dedicated area of the local cache of the controller, determining an address of the data in a global address space, the global address space corresponding to respective shared areas in the local caches of the plurality of controllers; and
searching the data using the address in the global address space.
2 . The method of claim 1 , wherein searching the data using the address in the global address space comprises:
determining whether the data is located in the shared area of the local cache of the controller.
3 . The method of claim 2 , further comprising:
in response to the data being located in the shared area of the local cache of the controller,
accessing the data from the shared area of the local cache of the controller; and
transmitting the data to the dedicated area of the local cache of the controller.
4 . The method of claim 2 , further comprising:
in response to the data being missed in the shared area of the local cache of the controller,
determining, using the address, a local cache of a further controller that stores the data;
obtaining the data from the local cache of the further controller; and
transmitting the data to the dedicated area of the local cache of the controller.
5 . The method of claim 1 , wherein the plurality of controllers communicates with each other through internal communication interfaces.
6 . An apparatus for data access in a storage system, the apparatus comprising:
an access request receiving unit configured to receive an access request for data from a controller among a plurality of controllers in the storage system, the plurality of controllers having respective local caches;
a dedicated area determining unit configured to determine whether the data is located in a dedicated area of the local cache of the controller;
a global address determining unit configured to, in response to the data being missed in the dedicated area of the local cache of the controller, determine an address of the data in a global address space, the global address space corresponding to respective shared areas in the local cache of the plurality of controllers; and
a data searching unit configured to search the data using the address in the global address space.
7 . The apparatus of claim 6 , wherein the data searching unit is further configured to:
determine whether the data is located in the shared area of the local cache of the controller.
8 . The apparatus of claim 7 , wherein the data searching unit is further configured to:
in response to the data being located in the shared area of the local cache of the controller,
access the data from the shared area of the local cache of the controller; and
transmit the data to the dedicated area of the local cache of the controller.
9 . The apparatus of claim 7 , wherein the data searching unit is further configured to:
in response to the data being missed in the shared area of the local cache of the controller,
determine, using the address, a local cache of a further controller that stores the data;
obtain the data from the local cache of the further controller; and
transmit the data to the dedicated area of the local cache of the controller.
10 . The apparatus of claim 6 , wherein the plurality of controllers communicates with each other through internal communication interfaces.
11 - 12 . (canceled)