Patent ID: 11003554

Abstract:
Techniques for providing metadata (and/or data) protection in a data storage system. The techniques can include storing, for a specific data page, two (2) instances of a main metadata page and one (1) instance of a corresponding alternative metadata page in a protected storage object referred to herein as the “2+1-way mirror”. For the specific data page, two (2) instances of a main metadata page can be stored on a first drive and a second drive, respectively, of the 2+1-way mirror such that the first and second drives each have a copy of the same main metadata page. Further, an instance of a corresponding alternative metadata page can be stored on a third drive of the 2+1-way mirror. The 2+1-way mirror provides protection against metadata loss due to the concurrent failure of two (2) physical drives, and further provides protection against catastrophic metadata errors and/or inconsistencies due to software failures.