International Business Machines Corporation

Hai Zhong Zhou

Frank Bernhard Schmuck

Felipe Knop

Deepavali M Bhagwat

Owen Theodore Anderson

Enci Zhong

Yong Sen Zheng

Guang Han Sui

Ji Dong Li

John Lewars

D Scott Guthridge

Lin Feng Shen

Shuo Feng

Wu Xu

Yu Bing Tang

A method for executing operation requests includes formatting one or more storage devices and selecting one or more labeled replicas and one or more distinguished replicas, receiving an operation request with respect to a set of data blocks, identifying a preferred replica corresponding to the received operation request, determining whether the replication-pending bits for the preferred replica are set, and executing the received operation request with respect to the corresponding distinguished replica. A method for executing a write operation request additionally includes setting replication-pending bits with respect to the labeled replica, wherein the replication-pending bits indicate an incomplete write request, writing data to both a labeled replica and a distinguished replica, and clearing the replication-pending bits with respect to the labeled replica to indicate the completion of the write operation. A method for executing a read operation additionally includes identifying a preferred replica with respect to the received read request.

Interrupted replicated write recognition

A method and a computer system for asymmetric replication of data are provided. Storage of a set of data is organized as a first copy and as a second copy in non-volatile storage. The second copy is reliable and stored so as to be readable at a speed slower than for the first copy. A read instruction regarding the set of data is received and performed preferentially via the first copy such that the asymmetric replication achieves enhanced performance speed. A request to execute a write operation is received. The write operation is executed to the first copy and to the second copy. In response to determining that the write operation to the first copy was unsuccessful, a label for the first copy is set as stale.

Efficient use of optional fast replicas via asymmetric replication

A computer-implemented method comprises initializing a plurality of segment lists. Each segment list of the plurality of segment lists corresponds to a respective one of a plurality of disk drives. Each segment list divides storage space of the respective disk drive into a plurality of segments. The method further comprises, for each of the plurality of disk drives, identifying one or more candidate segments from the plurality of segments; calculating a respective segment distance variance for one or more combinations of identified candidate segments. Each combination of identified candidate segments includes one candidate segment for each of the plurality of disk drives. The method further comprises selecting a combination of the one or more combinations of identified candidate segments having the smallest respective segment distance variance; and storing data on the plurality of disk drives according to the selected combination of identified candidate segments.

Disk offset-distance awareness data placement for storage system data protection

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Beijing, China

Hai Zhong Zhou