Dell Products Inc.

Emc IP Holding Company LLC

Daohong Wang

Peng Yin

Jiahui Wang

Michael J Scharland

Kuolin Hua

Stephen Richard Ives

Kunxiu Gao

Seema G Pai

Ningdong Li

Li Lang

Sean Hu

A method comprising: detecting a storage device failure in a storage array, the storage array including a plurality of storage devices, the storage device failure being a failure of one or more of the plurality of storage devices; wherein: the plurality of storage devices are configured to implement a supergroup including a plurality of subgroups; identifying ones of the plurality of subgroups that are affected by the storage device failure; and rebuilding the identified subgroups, wherein: (A) when a count of failed storage device is less than a first threshold, each of the identified subgroups is rebuilt based only on subgroup parity components for the subgroup without the use of supergroup parity components, and (B) when the count of failed storage devices is between the first threshold and the second threshold, each of the identified subgroups is rebuilt based on both subgroup and supergroup parity components.

Hierarchical parity protection groups for efficient data recovery

Techniques for performing configuration may include: determining an initial distribution of logical devices among disk adapters, wherein the initial distribution assigns each logical device a designated disk adapter as a primary active disk adapter servicing I/Os directed to the logical device, wherein the logical devices have storage provisioned from a RAID group including physical storage devices, wherein the disk adapters concurrently issue I/Os to each of the physical storage devices; detecting a configuration change; and responsive to detecting a configuration change, performing first processing. The first processing may include determining, in accordance with the configuration change, a redistribution of the logical devices among the disk adapters; and draining pending I/Os. The configuration change may include adding or removing a logical device provisioned from the RAID group. Performing a first operation on a storage device of the RAID group may include synchronous draining of I/Os of the storage device.

Techniques for multiple directors concurrently servicing I/Os directed to same physical storage devices

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Newton, MA, United States of America

Daohong Wang