Fibre Channel Storage Array Methods for Handling Cache-Consistency Among Controllers of an Array and Consistency Among Arrays of a Pool

Abstract

Storage arrays, systems and methods for operating storage arrays for maintaining consistency in configuration data between processes running on an active controller and a standby controller of the storage array are provided. One example method includes executing a primary process in user space of the active controller. The primary process is configured to process request commands from one or more initiators, and the primary process has access to a volume manager for serving data input / output (I / O) requests and non-I / O requests. The primary process has primary access to the configuration data and includes a first logical unit (LU) cache for storing the configuration data. The method also includes executing a secondary process in user space of the standby controller. The secondary process is configured to process request commands from one or more of the initiators, wherein the secondary process does not have access to the volume manger. The secondary process has a second LU cache for storing the configuration data, and the second LU cache is used by the secondary process for responding to non-I / O requests. The method includes receiving, at the primary process, an update to the configuration data and sending, by the primary process, the update to the configuration data to the secondary process for updating the second LU cache. When the primary process receives an acknowledgement from the secondary process that the update to the configuration data was received, then the updates to the configuration data are committed to the first LU cache of the active controller.

Description

CLAIM OF PRIORITY[0001]This application claims priority from U.S. Provisional Patent Application No. 62 / 050,680, filed on Sep. 15, 2014, entitled “Fibre Channel Storage Array Systems and Methods,” which is herein incorporated by reference.BACKGROUND[0002]1. Field of the Invention[0003]The present embodiments relate to storage arrays, methods, systems, and programs for maintaining a consistent cache of logical unit data and port data for Fibre Channel arrays, such as where storage arrays use fail-over processes and standby hardware to maintain high availability to initiators.[0004]2. Description of the Related Art[0005]Network storage, also referred to as network storage systems or storage systems, is computer data storage connected to a computer network providing data access to heterogeneous clients. Typically network storage systems process a large amount of Input / Output (I / O) requests, and high availability, speed, and reliability are desirable characteristics of network storage.[...

AI Technical Summary

Benefits of technology

The patent describes methods and systems for managing failover operations in a storage array. The system includes an active controller and a standby controller, each with a cache for storing configuration data. The system ensures that any changes made to the configuration data on the active controller are consistent with the standby controller. This ensures that both controllers have the correct configurations when failover occurs. The system also includes a configuration management unit that communicates changes to the configuration data to both controllers, who then commit the changes to their respective caches. This ensures that the standby controller has the most up-to-date information in case of failure. Overall, the system provides a reliable and consistent failover solution for storage arrays.

Problems solved by technology

Since the difference in access times between a cache memory and a hard drive are significant, the overall performance of the system is highly impacted by the cache hit ratio.

If initiators see storage arrays with excessive failures, even when a storage array is processing failover procedures, such storage arrays will be viewed as less than optimal.

Images