公开(公告)号：US20220342762A1

公开(公告)日：2022-10-27

申请号：US17237100

申请日：2021-04-22

Applicant: EMC IP Holding Company LLC

Inventor： Bhaskar Bora ,  Mark J. Halstead ,  Jeffrey Wilson

IPC: G06F11/14 ,  G06F3/06

Abstract: Snapshots of a first logical storage unit (LSU) (R1) on a first storage system (A1) may be taken while replication is inactive between A1 and a second storage system (A2), such that these outstanding snapshots are not replicated to a second replica LSU (R2) on A2. Upon replication becoming active, the outstanding snapshots may be replicated to R2 without disrupting or impairing the remote replication of write operations between R1 and R2 as part of standard remote replication. A process on A1 executing the replication of the outstanding snapshots from R1 to R2 may be a separate process than one or more processes on A1 executing standard remote replication including the replication of write operations from R1 to R2. The process may be given low priority on A1 so as to not impair performance of other operations, including standard remote replication and replicating outstanding write operations on A1.

公开(公告)号：US20220083564A1

公开(公告)日：2022-03-17

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：US10210059B1

公开(公告)日：2019-02-19

申请号：US15797739

申请日：2017-10-30

Applicant: EMC IP Holding Company LLC

Inventor： Bhaskar Bora

IPC: G06F3/06 ,  G06F11/20 ,  G06F11/34 ,  G06F11/30

Abstract: A method of IO workload selection and prioritization in data mirroring environments includes setting a first weight, a second weight, and a third weight to be used during an iteration of IO processing. The method further includes processing IOs of a first class of IO operations while there are IOs of the first class of IO operations to be processed and while a first weight for the first class of IO operations is positive, processing IOs of a second class of IO operations while there are IOs of the second class of IO operations to be processed and while a second weight for the second class of IO operations is positive, processing IOs of a third class of IO operations while there are IOs of the third class of IO operations to be processed and while a third weight for the third class of IO operations is positive.

公开(公告)号：US11709614B2

公开(公告)日：2023-07-25

申请号：US17383752

申请日：2021-07-23

Applicant: EMC IP Holding Company LLC

Inventor： Bhaskar Bora ,  Arieh Don

IPC: G06F3/06

CPC classification number: G06F3/065 ,  G06F3/0611 ,  G06F3/0659 ,  G06F3/0664 ,  G06F3/0673

Abstract: Snapshots are processed without holding all write operations while the snapshots are being activated. Rather than holding all write operations until snapshots are activated, write operations may be allowed to proceed. Snapshot write processing may be temporarily suspended while the snapshots are being activated, including snapshot metadata being updated, while write operations received while the snapshots are being activated are logged. After snapshots have been activated for all logical LSUs for which snapshots were instructed to be activated, the logging of write operations may be stopped, and the logged write entries processed to determine whether any of the logged write operations require updating snapshot information of any logical storage elements (LSEs) of the LSUs. While the logged write operations are being processed, any write operations received from a host for an LSE having a logged write operation may be held until the held operation, or all held operations are processed.

公开(公告)号：US11567876B2

公开(公告)日：2023-01-31

申请号：US17084835

申请日：2020-10-30

Applicant: EMC IP Holding Company LLC

Inventor： Bhaskar Bora ,  Benjamin Yoder

IPC: G06F12/0871 ,  G06F12/02 ,  G06F12/0813 ,  G06F12/0817

Abstract: Cache slots on a storage system may be shared between entities processing write operations for logical storage unit (LSU) tracks and entities performing remote replication for write operations for the LSU tracks. If a new write operation is received on a first storage system (S1) for a track of an LSU (R1) when the cache slot mapped to the R1 track is locked by a process currently transmitting data of the cache slot to a second storage system (S2), a new cache slot may be allocated to the R1 track, the data of the original cache slot copied to the new cache slot, and the new write operation for the R1 track initiated on S1 using the new cache slot; while the data of the original cache slot is independently, and perhaps concurrently, transmitted to S2 to be replicated in R2, the LSU on S2 that is paired with R1.

公开(公告)号：US20220342551A1

公开(公告)日：2022-10-27

申请号：US17238103

申请日：2021-04-22

Applicant: EMC IP Holding Company LLC

Inventor： Bhaskar Bora ,  Mark J. Halstead ,  Deepak Vokaliga ,  Benjamin Yoder ,  William R. Stronge

IPC: G06F3/06 ,  G06F11/14

Abstract: Snapshots may be used to implement remote replication, for example, asynchronously, between a first storage system, A1, and a second storage system, A2. A1 may take a first snapshot, SS21, of a logical storage unit, R1. After the snapshot SS21 it taken, any dependent write operations associated with SS21 may be reconciled, and differences between SS21 and the last snapshot for R1, SS11, may be determined and recorded as a difference set. One or more replication instructions for R1 that include the write operations (or data and metadata corresponding thereto) of the difference set may be sent from A1 to A2. A2 may apply the differences to R2, and then take (activate) a snapshot of R2, SS22, which is a replica of SS21. After A2 activates SS22, A2 may send an acknowledgement to A1 indicating that SS22 has been activated, and A2 may take a next snapshot of R1.

公开(公告)号：US10936451B2

公开(公告)日：2021-03-02

申请号：US16168910

申请日：2018-10-24

Applicant: EMC IP HOLDING COMPANY LLC

Inventor： Toufic Tannous ,  Bhaskar Bora ,  Deepak Vokaliga

IPC: G06F3/06 ,  G06F12/126 ,  G06F12/0868 ,  G06F12/084 ,  G06F12/02 ,  G06F11/20

Abstract: In a data storage system in which a first storage array and a second storage array maintain first and second replicas of a production volume, the first storage array is responsive to a write command from a host to send a notification to the second storage array indicating that the replicated production volume will be updated. The notification has information that enables the second storage array to implement pre-processing steps to prepare for subsequent receipt of data associated with the write command. Both storage arrays implement the pre-processing steps at least partly concurrently. When the data associated with the write command is subsequently received, the first storage array writes the data to cache and then sends a copy of the data to the second storage array, i.e. in series. The second storage array then writes the data to cache. Elapsed time between receipt of the write command and returning an acknowledgment to the host may be improved by concurrent pre-processing.

公开(公告)号：US10210098B1

公开(公告)日：2019-02-19

申请号：US15848682

申请日：2017-12-20

Applicant: EMC IP Holding Company LLC

Inventor： Benjamin Yoder ,  Bhaskar Bora

IPC: G06F12/121 ,  G06F12/0808

Abstract: Described are data replication techniques. Y cycles of writes directed to a first storage device of a first data storage system are collected, Y>2. Each of the Y cycles denotes writes directed to the first storage device at an occurrence of a fixed time interval. Writes of cycle N−1 directed to the first storage device are transmitted from the first data storage system to a second data storage system. Writes of cycle N−2 are applied to a second storage device. An acknowledgement regarding cycle N−1 is sent from the second data storage system 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 directed to the first storage device have been applied to the second storage device.

公开(公告)号：US12008018B2

公开(公告)日：2024-06-11

申请号：US17237127

申请日：2021-04-22

Applicant: EMC IP Holding Company LLC

Inventor： Bhaskar Bora ,  Deepak Vokaliga ,  Mark J. Halstead ,  Jeffrey Wilson ,  William R. Stronge ,  Ian Adams

IPC: G06F16/27 ,  G06F11/14

CPC classification number: G06F16/275 ,  G06F16/27 ,  G06F11/1446 ,  G06F2201/84

Abstract: Snapshots from a first LSU (R1) on a first storage system (A1) may be replicated to a second replica LSU (R2) on a second storage system (A2), for example, concurrently to remotely replicating (e.g., synchronously) write operations for R1 to R2. A process, P, on A1 executing the replication of the snapshots from R1 to R2 may be a separate process than the one or more processes on A1 executing remote replication of write operations for R1 to R2. During a consistency window on A1, outstanding write operations for R1 at the time the consistency window opened may be logged, and a pair of snapshots, SS11 and SS12 may be activated on R1 and R2, respectively. After the consistency window has closed, the SS12 snapshot metadata and snapshot data may be updated based on the outstanding write operations.

公开(公告)号：US11755230B2

公开(公告)日：2023-09-12

申请号：US17237171

申请日：2021-04-22

Applicant: EMC IP Holding Company LLC

Inventor： Ian Adams ,  Bhaskar Bora ,  Jeffrey Wilson

IPC: G06F3/06

CPC classification number: G06F3/065 ,  G06F3/067 ,  G06F3/0619 ,  G06F3/0659

Abstract: Snapshots may be remotely replicated asynchronously from a first LSU (R1) on a first storage system (A) to a second replica LSU (R2) on a second storage system (A2). The storage system A1 may open a consistency window to suspend initiating processing of new write operations received on A1. While the consistency window is open, A1 may: take a first snapshot, SS11, of R1; record, in association with the first replication cycle, an indication to replicate SS11 on A2; and initiate a next replication cycle to record write operations of the next new write requests to be received from hosts. After initiating a next replication cycle, A1 may close the consistency and transmit the first replication cycle to A2. A2 may apply the write operations of the first replication cycle to R2, and then take a second snapshot SS12 of R2, which should be a replica of SS11.