CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Chinese Patent Application No. CN201811290049.X, on file at the China National Intellectual Property Administration (CNIPA), having a filing date of Oct. 31, 2018, and having “METHOD, DEVICE, AND PROGRAM PRODUCT FOR REDUCING DELAY IN I/O PROCESSING DUE TO MIRRORING OF CACHE DATA” as a title, the contents and teachings of which are herein incorporated by reference in their entirety.

FIELD

Embodiments of the present disclosure generally relate to a computer system or a storage system, and more specifically, to a method, an electronic device and a computer program product for reducing latency of mirroring cache data in I/O handling.

BACKGROUND

Typically, users of a storage system may access the storage system with a host. Application software may run on the host, and the storage system provides service of data storage to the host. A front end bus may be used for data transfer between the host and the storage system. As the name suggests, in a dual processor storage system, there are two processors for providing storage service to the host, which may be referred to as storage processors (SPs). The two processors may be connected via an internal communication channel which, for example, may be referred to as communication manager interface (CMI). The two processors may synchronize data and internal states to each other through the communication channel, and so on. At a back end of the storage system, storage disks may be connected to the two processors via a back end bus.

However, in a conventional dual processor storage system, there are still a lot of problems in operations of data mirroring between the two processors, for example, a complicated flow for responding to I/O requests sent from a host, overlong latency, poor performance and the like. This makes the conventional dual processor storage system cannot satisfy users' demands in many scenarios, leading to a poor user experience.

SUMMARY

Embodiments of the present disclosure relate to a method, an electronic device and a computer program product for reducing latency of mirroring cache data in I/O handling.

In a first aspect of the present disclosure, there is provided a method of storage management. The method includes: in response to receiving, at a first processor of a storage system, a write request from a host for writing user data to the storage system, caching the user data in a first cache of the first processor, and generating cache metadata in the first cache, the cache metadata including information associated with writing the user data to the storage system; sending the user data and the cache metadata to a second cache of a second processor of the storage system, for the second processor to perform, in the second cache data processing related to cache mirroring; and sending, to the host, an indication of completion of the write request, without waiting for the second processor to complete the data processing.

In a second aspect of the present disclosure, there is provided a method of storage management. The method includes: receiving, at a second processor of a storage system, user data and cache metadata from a first cache of a first processor of the storage system, the cache metadata including information associated with writing the user data to the storage system; preprocessing the cache metadata, such that the user data is accessible to a host via the second processor; and performing, in a second cache of the second processor, data processing related to cache mirroring based on the user data and the cache metadata.

In a third aspect of the present disclosure, there is provided an electronic device. The electronic device includes at least two processors and at least one memory storing computer program instructions. The at least one memory and the computer program instructions are configured, together with the at least two processors, to cause the electronic device to: in response to receiving, at a first processor, a write request from a host for writing user data to the storage system, cache the user data in a first cache of the first processor, and generate cache metadata in the first cache, the cache metadata including information associated with writing the user data to the storage system; send the user data and the cache metadata to a second cache of a second processor, for the second processor to perform, in the second cache, data processing related to cache mirroring; and send, to the host, an indication of completion of the write request, without waiting for the second processor to complete the data processing.

In a fourth aspect of the present disclosure, there is provided an electronic device. The electronic device includes at least two processors and at least one memory storing computer program instructions. The at least one memory and the computer program instructions are configured, together with the at least two processors, to cause the electronic device to: receive, at a second processor, user data and cache metadata from a first cache of a first processor, the cache metadata including information associated with writing the user data to the storage system; preprocess the cache metadata, such that the user data is accessible to a host via the second processor; and perform, in a second cache of the second processor, data processing related to cache mirroring based on the user data and the cache metadata.

In a fifth aspect of the present disclosure, there is provided a computer program product. The computer program product is tangibly stored on a non-volatile computer-readable medium and includes machine-executable instructions which, when executed, cause a machine to perform steps of the method according to the first aspect.

In a sixth aspect of the present disclosure, there is provided a computer program product. The computer program product is tangibly stored on a non-volatile computer-readable medium and includes machine-executable instructions which, when executed, cause a machine to perform steps of the method according to the second aspect.

It would be appreciated that this Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other features of the present disclosure will be made apparent by the following description.

