公开(公告)号：US11468091B2

公开(公告)日：2022-10-11

申请号：US17023525

申请日：2020-09-17

Applicant: EMC IP Holding Company LLC

Inventor： Bhaskar Bora ,  Mark J. Halstead ,  Michael E. Specht ,  Benjamin Yoder ,  Deepak Vokaliga

IPC: G06F16/27 ,  G06F12/0802

Abstract: Maintaining consistency for asynchronous replication of LUNs of a local storage system to corresponding LUNs of a remote storage system includes copying application data written to LUNs to cache slots, copying metadata of LUNs to cache slots, associating a first sequence number to all metadata modifications and all application data writes that are begun after a first time and before a second time, associating a second sequence number, different from the first sequence number, to all metadata modifications and all application data writes that are begun after the second time, and, after completion of all metadata modifications and all application data writes associated with the first sequence number, initiating transfer to the remote storage system of all metadata modifications and all application data writes associated with the first sequence number. Each cache slot may include a field that indicates a corresponding sequence number.

公开(公告)号：US10223402B1

公开(公告)日：2019-03-05

申请号：US14982218

申请日：2015-12-29

Applicant: EMC IP Holding Company LLC

Inventor： Deepak Vokaliga ,  Benjamin Yoder ,  George Quill

IPC: G06F17/30 ,  H04L29/08 ,  G06F11/14

Abstract: Maintaining write consistency between at least two mirrored storage devices includes receiving a write request for a particular block, obtaining a reservation for the particular block, waiting for the particular block to become available in response to not being able to successfully obtain the reservation, writing the particular block in response to successfully obtaining the reservation, and writing the particular block at a remote one of the storage devices following writing the particular block at the particular one of the storage devices. If a retryable indicator is received, the system waits a predetermined amount of time and releases the reservation. The system responds with a success indicator when writing the particular block at a remote one of the storage devices succeeds and responds with a failure indicator when writing the particular block at a remote one of the storage devices fails and the retryable indicator is not received.

公开(公告)号：US10200304B1

公开(公告)日：2019-02-05

申请号：US14982776

申请日：2015-12-29

Applicant: EMC IP Holding Company LLC

Inventor： Deepak Vokaliga ,  Svetlana O. Sokolova ,  Mark J. Halstead ,  Benjamin Yoder

IPC: H04L12/911

Abstract: Managing reservations for at least two different sites competing for a resource includes maintaining a table of groups of sites, where each group competes for the same resource, one of the different sites requesting a reservation for a particular resource, determining if the reservation is available by consulting the table, denying the reservation to the one of the at least two different sites in response to access having been previously reserved for an other one of the different sites, and granting the reservation to the one of the at least two different sites and reserving access for the one of the at least two different sites in response to the resource being available. The managed resources may correspond to data storage and the two different sites may be mirrored storage devices. In response to a failure of communication between the two different sites, pending writes may be failed.

公开(公告)号：US10146648B1

公开(公告)日：2018-12-04

申请号：US15281599

申请日：2016-09-30

Applicant: EMC IP HOLDING COMPANY LLC

Inventor： Deepak Vokaliga ,  Sandeep Chandrashekara ,  Benjamin Yoder ,  Deepika Kini

IPC: G06F11/20 ,  G06F3/06 ,  G06F11/14 ,  H04L29/08

Abstract: Replication of a storage object to a remote storage array is seamlessly maintained by i) while write operations directed to the storage object are being collected into a set of write cycles that are stored in a master storage array, also collecting the write operations directed to the storage volume into a set of write cycles stored in a slave storage array, and ii) in response to detecting a failure of the master storage array, and while the host computer continues to access the storage object using a copy of the storage object located in the slave storage array, transmitting the write cycles stored in the slave storage array to the remote storage array, so that the remote storage array can apply the write operations in the write cycles it receives from the slave storage array on the copy of the storage object contained in the remote storage array.

公开(公告)号：US09880758B1

公开(公告)日：2018-01-30

申请号：US14672652

申请日：2015-03-30

Applicant: EMC IP Holding Company LLC

Inventor： Bhaskar Bora ,  Benjamin Yoder

IPC: G06F12/00 ,  G06F3/06

CPC classification number: G06F3/0619 ,  G06F3/061 ,  G06F3/065 ,  G06F3/0665 ,  G06F3/0689 ,  G06F2003/0692

Abstract: Described are data replication techniques. Writes of cycle N directed to a first storage device of a first data storage system are received. Writes of cycle N−1 directed to the first storage device are transmitted to a second data storage system. Writes of cycle N−2 directed to the first storage device are applied to a second storage device of the second data storage system. An acknowledgement regarding cycle N−1 is sent to the first data storage system responsive to determining that the writes of cycle N−1 directed to the first storage device have been received by the second data storage system and that the writes of cycle N−2 have been applied to the second storage device. At least some writes of cycle N directed to the first storage device are transmitted to the second data storage system prior to the first data storage system receiving the acknowledgement regarding cycle N−1.