公开(公告)号：US20220350491A1

公开(公告)日：2022-11-03

申请号：US17306424

申请日：2021-05-03

Applicant: EMC IP HOLDING COMPANY LLC

Inventor： Bhaskar Bora ,  Jeffrey Wilson ,  Michael Ferrari ,  William Stronge ,  Sandeep Chandrashekhara

IPC: G06F3/06

Abstract: A target-less point in time image (snapshot) of a storage volume is allowed to be built after activation, by enabling the snapshot data to be modified to create a crash-consistent replica of the source data after the snapshot has been activated. The data of the snapshot remains immutable from a user standpoint, but the snapshot is able to be quickly activated before all of the data of the snapshot has been included in the snapshot, to thus reduce an amount of time IO operations on the source volume are quiesced. A first snapshot of a storage volume is created on a primary storage system and a corresponding second snapshot of the storage volume is activated on a backup storage system before all the data of the first snapshot is received at the backup storage system. Entries of the activated second snapshot are then changed to point to correct back-end allocations.

公开(公告)号：US11340795B2

公开(公告)日：2022-05-24

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 ,  G06F11/14

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：US20210374007A1

公开(公告)日：2021-12-02

申请号：US16886840

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: G06F11/14 ,  G06F16/11

Abstract: Targetless snapshot schedules are defined by policy objects that include a snap creation interval, maximum snap count, and schedule ID. Multiple schedule IDs can be associated with a single storage object to implement different concurrent targetless snapshot schedules with a single storage object. Multiple storage objects may use the same targetless snapshot schedule independently. Because the targetless snapshot schedules are implemented independently, discard of old snapshots to maintain a snap count for a first storage object does not cause discard of snapshots for a second storage object. Further, discard of old snapshots to maintain a snap count for a first schedule does not cause discard of snapshots for a second schedule applied to the same storage object.

公开(公告)号：US10853389B2

公开(公告)日：2020-12-01

申请号：US15969048

申请日：2018-05-02

Applicant: EMC IP Holding Company LLC

Inventor： Sandeep Chandrashekhara ,  Michael Ferrari ,  George F. Lettery ,  Nicholas W. Von Hein ,  Shruti Gupta

IPC: G06F7/00 ,  G06F16/27 ,  G06F12/0875 ,  G06F16/11

Abstract: Techniques for providing snapshots of logical devices may include: receiving a first request to create a first snapshot of a logical device; responsive to the first request, performing first processing including storing first information in a cache slot, the first information identifying the first snapshot and the logical device used as a source of the first snapshot; receiving a second request to activate one or more snapshots, including the first snapshot, identified by information stored in the cache slot; and responsive to receiving the second request, performing second processing including initiating execution of an asynchronous process that performs snapshot activation processing for the one or more snapshots identified by the cache slot.

公开(公告)号：US20220229806A1

公开(公告)日：2022-07-21

申请号：US17154332

申请日：2021-01-21

Applicant: EMC IP HOLDING COMPANY LLC

Inventor： John Copley ,  Daryl Kinney ,  Tao Tao ,  Shakil Anwar ,  Michael Ferrari ,  Nicholas von Hein

IPC: G06F16/11 ,  G06F16/14

Abstract: Snapsets containing snapshots from a group of storage volumes are assigned snapset IDs. The same snapset ID is applied to each snapshot of the snapset, and is a globally unique value within the storage system. The snapset ID is assigned to a snapshot upon creation, and remains the same regardless of creation or deletion of other snapshots on the storage volume. By assigning a snapset ID to each snapshot of the snapset, and maintaining the snapset ID as a constant value as long as the snapshot is maintained on the storage system, it is possible to easily determine which snapshots form a given snapset. Control operations on particular storage groups or across storage groups are implemented by specifying particular actions to be taken on snapsets or snapshots, which are identified using the snapset IDs.

公开(公告)号：US20210374096A1

公开(公告)日：2021-12-02

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：US20210373780A1

公开(公告)日：2021-12-02

申请号：US16885542

申请日：2020-05-28

Applicant: EMC IP HOLDING COMPANY LLC

Inventor： Michael Ferrari ,  Jeffrey Wilson ,  Sandeep Chandrashekhara

IPC: G06F3/06 ,  G06F11/14

Abstract: Storage objects and targetless snaps of the storage objects are represented using a system replication data pointer table (SRT), direct index lookup (DIL) tables, and virtual replication data pointer tables (VRTs). The SRT is a system level track-based data structure that stores metadata indicative of the actual (physical layer) allocations for all targetless snapshots in a storage array. The size of the SRT in terms of total entries corresponds to the overall storage capacity of the managed drives of the storage array. Each utilized entry of the SRT includes backend metadata with a pointer to a managed drive and metadata that identifies the associated storage object and track via the VRTs and DIL tables. SRT metadata is created and discarded as backend allocations are utilized and freed so the SRT is a dynamic data structure that can efficiently adjust its size and corresponding memory requirements.

公开(公告)号：US11188425B1

公开(公告)日：2021-11-30

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：US10852952B1

公开(公告)日：2020-12-01

申请号：US16519303

申请日：2019-07-23

Applicant: EMC IP Holding Company LLC

Inventor： Jaeyoo Jung ,  Michael Ferrari ,  Arieh Don

IPC: G06F3/06 ,  G06F11/14

Abstract: Techniques for processing I/O operations may include: selecting a logical device having at least one snapshot on a data storage system; sending, from a host to the data storage system, a first hint for a first write I/O operation directed to a first location on the logical device, wherein said sending the first hint is performed prior to the host sending the first write I/O operation to the data storage system; and responsive to receiving the first hint regarding the first write I/O operation to the first location of the logical device having at least one snapshot, performing preprocessing for the first write I/O operation. Hints may also be sent for I/O operations directed to a target device linked to a snapshot of the logical device. The data storage system may perform preprocessing for the I/O operations directed to the target device linked to the snapshot.

公开(公告)号：US10824513B1

公开(公告)日：2020-11-03

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: G06F12/00 ,  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.