公开(公告)号：US11237916B2

公开(公告)日：2022-02-01

申请号：US16692742

申请日：2019-11-22

Applicant: EMC IP Holding Company LLC

Inventor： Sandeep Chandrashekhara ,  Michael Ferrari ,  Jeffrey Wilson ,  Mark J. Halstead ,  Art Longden

IPC: G06F11/14 ,  G06F12/1009

Abstract: A no-copy clone of a logical storage unit is created. A define process is initiated for defining a target logical storage unit as the clone before activation of the target logical storage unit. By initiating the define process before activating the logical storage unit, there is a greater likelihood that, when a write operation is received for a data portion on the source logical storage unit or target logical storage unit after activation of the target LSU, the data portion will already be defined and not need to be defined when performing the write operation. When a write operation is received at the source logical storage unit, if the target logical storage unit is not active yet, the data of the write operation may be written to an allocated physical location for the data portion shared between the source and target logical storage units without updating any clone metadata.

公开(公告)号：US20210374017A1

公开(公告)日：2021-12-02

申请号：US16885702

申请日：2020-05-28

Applicant: EMC IP Holding Company LLC

Inventor： Kevin M. Tobin ,  Andrew L. Chanler ,  Michael Ferrari ,  Jeffrey Wilson

IPC: G06F11/14 ,  G06F3/06

Abstract: Snapshots may be managed on a data storage system including logical storage unit including data portions. For a first logical storage unit, a first snapshot pointer structure may be provided including entries, each entry corresponding to a physical storage location at which data is stored for a data portion of the first logical storage unit at a particular point in time. A first virtual snapshot lookup table may be provided for a first portion of the first logical storage unit, the first virtual snapshot lookup table including a plurality of entries, each entry corresponding to a respective data portion of the first logical storage unit and including a reference to a respective entry of the first snapshot pointer structure. The virtual lookup table may correspond to multiple snapshots of the first logical storage unit that have a same value for each data portion of the at least first portion.

公开(公告)号：US20210373781A1

公开(公告)日：2021-12-02

申请号：US16885662

申请日：2020-05-28

Applicant: EMC IP Holding Company LLC

Inventor： Jeffrey Wilson ,  Michael Ferrari ,  Mark J. Halstead ,  Sandeep Chandrashekara

IPC: G06F3/06

Abstract: A snapshot lookup table (SLT) and snapshot pointer structure(s) (SPSs) may be provided for a logical data unit (LSU), each SPS entry corresponding to an LSU data portion and a physical storage location at which data is stored for the data portion for a particular snapshot. A current lookup table (CLT) for a current time may be provided for an LSU, including an entry for each LSU data that points to a respective entry of an SPS. Each time a first write following the creation of a snapshot is made to an LSU data portion, the corresponding CLT entry may be updated to point to the SPS entry that was updated to point to an LSU track table entry. To create a snapshot, a snapshot lookup table (SLT) is created for each snapshot, and the contents of the CLT are copied to the newly created SLT.

公开(公告)号：US20210133098A1

公开(公告)日：2021-05-06

申请号：US16671372

申请日：2019-11-01

Applicant: EMC IP Holding Company LLC

Inventor： Jeffrey Wilson ,  Michael Ferrari ,  Shruti Gupta ,  George F. Lettery

IPC: G06F12/02

Abstract: Snapshot metadata may include a plurality of pages of nodes, including active nodes and free nodes. It may be determined whether a snapshot metadata object is eligible for de-allocation, for example, of one or more of the pages of its snapshot metadata nodes. This determination may be based on a number of free nodes in the snapshot metadata object, for example, in relation to the quantity of nodes that are included in a snapshot metadata page. This determination may be made based on previous usage of the nodes allocated to the snapshot metadata object, for example, the number of active nodes relative to a total size of the snapshot metadata object. For example, a maximum extent of active nodes during one or more periods may be compared to a current extent of active nodes to determine whether the snapshot metadata object is eligible.

公开(公告)号：US20200349020A1

公开(公告)日：2020-11-05

申请号：US16398879

申请日：2019-04-30

Applicant: EMC IP Holding Company LLC

Inventor： Sandeep Chandrashekhara ,  David T. Tsang ,  Michael Ferrari ,  Jeffrey Wilson ,  Mark J. Halstead

IPC: G06F11/14 ,  G06F3/06

Abstract: An apparatus in one embodiment comprises at least one processing device having a processor coupled to a memory. The processing device is configured to maintain, for logical storage volumes of a storage system, device sequence numbers for snapshot and extent copy operations. The processing device is also configured to maintain, for at least one track of the logical storage volumes, a track sequence number representing the state of the track with respect to the snapshot and extent copy operations. The processing device is further configured to receive input/output operations directed to the logical storage volumes from host devices coupled to the storage system while at least one snapshot or extent copy operation for the logical storage volumes is in progress, and to utilize the track sequence numbers and the device sequence numbers to determine processing of the received input/output operations while the snapshot or extent copy operations are in progress.

公开(公告)号：US11429559B2

公开(公告)日：2022-08-30

申请号：US16886848

申请日：2020-05-29

Applicant: EMC IP HOLDING COMPANY LLC

Inventor： Nicholas Von Hein ,  Michael Ferrari ,  Daryl Kinney ,  Shakil Anwar ,  Tao Tao

IPC: G06F16/11

Abstract: Targetless snapshots that are in use are excluded from discard and exempted from inclusion against a snapshot retention count limit. Snapshots that are linked to a target volume are considered to be in use. Snapshots having a persist attribute set are considered to be in use. Snapshots having an expiration attribute set are considered to be in use until at least the expiration time. Snapshots having an age limit attribute set are considered to be in use until reaching at least the specified age. The snapshot retention count limit can be updated with a command. Other commands discard snapshots created before a specified time or older than a specified age, provided the snapshots are not in use. A terminate all command prompts discard of all snapshots that are not in use.

公开(公告)号：US11281540B2

公开(公告)日：2022-03-22

申请号：US16776615

申请日：2020-01-30

Applicant: EMC IP HOLDING COMPANY LLC

Inventor： Akshay Kumar Srivastava ,  Sandeep Chandrashekhara ,  Michael Ferrari ,  Deepak Vokaliga ,  Darren Fernandes

IPC: G06F16/27 ,  G06F11/14 ,  G06F16/21

Abstract: A remote data facility includes a primary storage volume on a first storage system mirrored to a backup storage volume on a second storage system. A nocopy clone of a production volume is added to the primary storage volume. A define process is used to cause the tracks of the nocopy clone to point to backend allocations of tracks of memory of the production volume. As tracks of the nocopy clone are defined, corresponding flags are marked as invalid to cause data associated with the tracks to be replicated across the remote data facility to the backup storage volume. Incremental clones can be added to the primary storage volume, defined, and replicated on the remote data facility using the same process. Nocopy clones and target-less nocopy snapshots of the backup storage volume are used to restore the production volume using failover/failback mechanisms of the remote data facility.

公开(公告)号：US20210374095A1

公开(公告)日：2021-12-02

申请号：US16885495

申请日：2020-05-28

Applicant: EMC IP HOLDING COMPANY LLC

Inventor： Jeffrey Wilson ,  Michael Ferrari ,  Sandeep Chandrashekhara

IPC: G06F16/11 ,  G06F16/188 ,  G06F16/182 ,  G06F16/901

Abstract: A first direct index lookup table represents the current state of a storage object using entries with references corresponding to tracks of the storage object. A second direct index lookup table represents a first targetless snapshot of the storage object. A virtual replication data pointer table maps the entries of both the first direct index lookup table and the entries of the second direct index lookup table to backend storage via a system replication data pointer table. Updates to the storage object are represented using new entries in the first direct index lookup table and the system replication data pointer table. Movement of a track that is represented in multiple targetless snapshots that are represented by multiple direct index lookup tables is represented by updating the corresponding virtual replication data pointer table and system replication data pointer table rather than updating each of the direct index lookup tables.

公开(公告)号：US11100008B2

公开(公告)日：2021-08-24

申请号：US16672228

申请日：2019-11-01

Applicant: EMC IP Holding Company LLC

Inventor： Jeffrey Wilson ,  Michael Ferrari ,  Shruti Gupta ,  George F. Lettery

IPC: G06F12/122

Abstract: Memory may be used more efficiently for snapshot metadata by reducing a size of a snapshot metadata object, for example, by removing free nodes from the snapshot metadata object. Removing free nodes may include consolidating free nodes into a single page of a snapshot metadata object and de-allocating the page from the memory allocated for the data structure. Consolidation of free nodes may be achieved by identifying active nodes in the single page, and swapping these active nodes with free nodes from other pages until the single page includes only free nodes. The nodes of the single page that were already free and the active nodes that were swapped with free nodes from another page may be designated for de-allocation. This designating may result in all nodes of the single page being designated for de-allocation, after which the single page of nodes may be de-allocated.

公开(公告)号：US20210240568A1

公开(公告)日：2021-08-05

申请号：US16776615

申请日：2020-01-30

Applicant: EMC IP HOLDING COMPANY LLC

Inventor： Akshay Kumar Srivastava ,  Sandeep Chandrashekhara ,  Michael Ferrari ,  Deepak Vokaliga ,  Darren Fernandes

IPC: G06F11/14 ,  G06F16/27 ,  G06F16/21

Abstract: A remote data facility includes a primary storage volume on a first storage system mirrored to a backup storage volume on a second storage system. A nocopy clone of a production volume is added to the primary storage volume. A define process is used to cause the tracks of the nocopy clone to point to backend allocations of tracks of memory of the production volume. As tracks of the nocopy clone are defined, corresponding flags are marked as invalid to cause data associated with the tracks to be replicated across the remote data facility to the backup storage volume. Incremental clones can be added to the primary storage volume, defined, and replicated on the remote data facility using the same process. Nocopy clones and target-less nocopy snapshots of the backup storage volume are used to restore the production volume using failover/failback mechanisms of the remote data facility.