Emc Corporation

Emc IP Holding Company LLC

Dell Products Inc.

Mark J Halstead

David Meiri

Benjamin W Yoder

Dan Arnon

Marik Marshak

Douglas Eric LeCrone

Haim Kopylovitz

Adi Ofer

Hana Moreshet

Vadim Longinov

Brett A Quinn

Gary H Cox

Peter Kamvysselis

Sandeep Chandrashekhara

Bhaskar Bora

Alexandr Veprinsky

Michael Ferrari

Jeffrey Wilson

Deepak Vokaliga

Kevin C Heasley

Mike Specht

Assaf Natanzon

Michael J Scharland

Rong Yu

Michael E Specht

William P Thibodeau

Saar Cohen

Rivka Mayraz Matosevich

Adnan Sahin

Peng Wu

William R Stronge

Prakash Venkatanarayanan

Jeremy O'Hare

Gaurav Bhatnagar

Peter Kamvysselisi

Arieh Don

Owen Martin

David Lionel Black

Dmitry Nikolayevich Tylik

Steven T McClure

John K Walton

Kendell Alan Chilton

Anestis Panidis

Brett D Niver

Alexey Vladimirovich Shusharin

Gilad Sade

Ofer Michael

Xiali He

Chakib Ouarraoui

John Krasner

Robert DeCrescenzo

Michael Bermingham

Serge Joseph Pirotte

Kaustubh S Sahasrabudhe

Ramprasad Shetty

James M McGillis

Sergey Kornfeld

Svetlana Sokolova

Benoit Joseph Merlet

Ziv Dor

Ian Adams

Erin Bournival

Sandeep Chandrashekara

Ilya Garelik

Oliver M D Shorey

Dharmesh Thakkar

David T Tsang

Art Longden

Gaurav Mukul Bhatnagar

William R Smith-Vaniz

A first storage system receives a request to migrate a volume from the first storage system to a second storage system, and commences a migration process to non-disruptively migrate the volume from the first storage system to the second storage system while the volume is being accessed by a host system. The first storage system sends a first request to the host system to discover information for connecting to the second storage system to allow the host system to access to the volume through the second storage system during the migration process. In addition, the first storage system sends a second request to the host system to discover information for disconnecting from the first storage system during a final stage of the migration process.

Managing host connectivity during non-disruptive migration in a storage system

A technique for deploying virtual volumes in a metro cluster across first and second arrays includes impersonating a third array that purports to host single-site virtual volumes. The technique further includes mapping the single-site virtual volumes purportedly hosted by the third array to respective pairs of actual virtual volumes. Each pair includes a first virtual volume in the first array and a second virtual volume in the second array and realizes a stretched virtual volume, with writes being mirrored between the virtual volumes of each pair.

Metro cluster for virtual volumes

A storage system is configured to accept subsequent versions of write data on a given track to multiple respective slots of shared global memory. A track index table presents metadata at the track level, and can hold up to N slots of data. All slots of shared global memory holding data owed to the source volume and to snapshots of the source volume are bound to the track in the track index table. Each time a write occurs on a track, the track index table is used to determine when a write pending slot for the track is owed to a snapshot copy of the storage volume. When a write pending slot contains data that is owed to a snapshot copy of the source volume, a new slot is allocated to the write IO and bound to the track in the track index table.

Multiple version write pending support in shared global memory

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, SS1and SS1may be activated on R1 and R2, respectively. After the consistency window has closed, the SS1snapshot metadata and snapshot data may be updated based on the outstanding write operations.

Synchronous remote replication of snapshots

Techniques are provided for load balancing in a storage system using a storage system-driven host connectivity management process. For example, a load balancing process comprises monitoring a distribution of input/output (I/O) workload across resources of a storage system to detect for an occurrence of an I/O workload imbalance, generating updated connection information for a host system connected to the storage system, in response to detecting the occurrence of an I/O workload imbalance, and sending a request to the host system to discover the updated connection information for connecting to the storage system based on the updated connection information.

Load balancing using storage system driven host connectivity management

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, SS2, of a logical storage unit, R1. After the snapshot SS2it taken, any dependent write operations associated with SS2may be reconciled, and differences between SS2and the last snapshot for R1, SS1, 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, SS2, which is a replica of SS2. After A2 activates SS2, A2 may send an acknowledgement to A1 indicating that SS2has been activated, and A2 may take a next snapshot of R1.

Snapshot-based remote replication

Aspects of the present disclosure relate to data cache management. In embodiments, a logical block address (LBA) bucket is established with at least one logical LBA group. Additionally, at least one LBA group is associated with two or more distinctly sized cache slots based on an input/output (IO) workload received by the storage array. Further, the association includes binding the two or more distinctly sized cache slots with at least one LBA group and mapping the bound distinctly sized cache slots in a searchable data structure. Furthermore, the searchable data structure identifies relationships between slot pointers and key metadata.

Cache memory architecture and management

Aspects of the present disclosure relate to improving response rates of input/output (IO) requests targeting undefined virtual storage devices. In embodiments, an (IO request can be received by a storage array. Additionally, a determination of whether the IO request targets an undefined target track can be made. Further, source data related to the IO request can be located. For instance, a direct image lookup (DIL) can be performed to locate the source data. Also, a storage-related operation on the undefined target track can be performed using instructions provided by the IO request, such as updating a version of the undefined track. Further, a storage resource allocation for the undefined target track can be destaged.

Undefined target volume input/output (IO) optimization

One or more aspects of the present disclosure relate to allocating virtual memory to one or more virtual machines (VMs). The one or more VMs can be established by a hypervisor of a storage device. The virtual memory can be allocated to the established one or more VMs. The virtual memory can correspond to non-volatile (NV) memory of a global memory of the storage device.

Providing non-volatile storage for permanent data to virtual machines

Aspects of the present disclosure relate to data cache management. In embodiments, a storage array's memory is provisioned with cache memory, wherein the cache memory includes one or more sets of distinctly sized cache slots. Additionally, a logical storage volume (LSV) is established with at least one logical block address (LBA) group. Further, at least one of the LSV's LBA groups is associated with two or more distinctly sized cache slots based on an input/output (IO) workload received by the storage array.

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.

Remote replication of snapshots taken while replication was inactive

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.

Maintaining consistency of asynchronous replication

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.

Snapshot metadata management

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.

Efficient cloning of logical storage devices

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.

Processing input/output operations while snapshot and extent copy operations are in progress for a logical storage volume

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Holliston, MA, United States of America

Mark J Halstead