Abstract: An apparatus in one embodiment comprises at least one processing device comprising a processor coupled to a memory. The at least one processing device is configured to identify a storage volume to be added to a first consistency group of a first synchronous replication session between a first storage system and a second storage system in an active-active configuration, to create a second synchronous replication session for the added storage volume between the first storage system and the second storage system, and to merge the first and second synchronous replication sessions responsive to one or more designated criteria. The second synchronous replication session is illustratively configured to be fully independent of the first synchronous replication session.

Abstract: In one aspect, automatic recovery of a synchronous replication session in response to an error is provided for a storage system that includes a source and target sites. During an active sync replication session in which a state machine indicates the system is operating in sync, an aspect includes monitoring input/output (IO) operations. Upon determining an occurrence of the error in which data has been persisted at the source site but not at the target site, an aspect includes discontinuing replication to the target site and transitioning the state machine from a sync state to a tripped state. Upon determining, during the tripped state, resources exist to conduct sync replication remote data transfer operations, transition the state machine to an async_to_sync state. The async_to_sync state causes the storage system to initiate a recovery operation to return the source and target sites to the sync state.

Abstract: Techniques for providing a direct IO path to compressed data on storage media of a storage system. The techniques include triggering a transaction cache to perform a flush operation for updating mapping metadata for a storage object containing the compressed data. Having updated the mapping metadata for the storage object, the techniques further include issuing, by a copier module, an IO read request for the compressed data of the storage object to a namespace layer, which issues the IO read request to a mapping layer. The techniques further include forwarding the IO read request to a logical layer of the mapping layer, bypassing the transaction cache. The techniques further include reading, by the logical layer, the compressed data of the storage object from the storage media, and providing, via the mapping layer and the namespace layer, the compressed data to the copier module for transfer to a destination storage system.

Abstract: An aspect of performing on-demand remote snapshot creation for a synchronous replication session between a local system and a remote system of a storage system includes receiving a request for the remote snapshot on the remote system and identifying a current state of the synchronous replication session. The current state is one of a plurality of states. An aspect also includes implementing one or more actions with respect to the remote snapshot as a function of the current state. The actions are performed prior to transitioning from the current state to another state of the plurality of states.

Abstract: An apparatus includes at least one processing device comprising a processor coupled to a memory, with the processing device being configured to maintain at least first and second journals for respective first and second different types of input-output requests, to move one or more entries between the first journal and the second journal under one or more specified conditions, to perform a clean-up operation for at least one of the first and second journals in conjunction with the moving of the one or more entries, and responsive to a failure occurring during the clean-up operation, to execute a contention resolution algorithm to resolve logical address range lock contentions between different entries of the first and second journals. The processing device illustratively comprises a storage controller of a storage system. The storage system may be, for example, a source storage system configured to carry out a synchronous replication process with a target storage system.

Abstract: A method is disclosed comprising: generating a first snapshot of a first storage subsystem; detecting, by a management node, that all in-flight data storage requests recorded in drain tables of storage nodes in the first storage subsystem have been completed, the in-flight data storage requests recorded in the drain tables of the storage nodes being replicated in a second storage subsystem; causing, by the management node, each of the storage nodes to flip the respective designations of the tracking tables in the node's respective pair of tracking tables; and transmitting, from the management node to the second storage subsystem, an instruction which when received by the second storage subsystem causes the second storage subsystem to generate a second snapshot of the second storage subsystem.

Abstract: At least one processing device receives a create-token command from a host device. Responsive to receipt of the create-token command, the processing device creates the token, generates an in-memory snapshot of data in one or more logical address ranges of one or more source storage volumes, associates the in-memory snapshot with the token, and provides the token to the host device. The processing device receives a write-via token command from the host device, the write-via-token command specifying the token and one or more logical address ranges of one or more target storage volumes. Responsive to receipt of the write-via-token command, the processing device determines whether or not differential metadata of the storage system includes one or more entries for the one or more logical address ranges of the one or more source storage volumes, and controls execution of the write-via-token command based at least in part on the determination.

Abstract: A method, computer program product, and computer system for receiving, at a computing device, a write request from a host, wherein a first portion of a process may receive the write request. A callback and context may be set in the write request by the first portion of the process. The write request may be passed to a second portion of the process. The first process may be provided with the context. The first process may use the context to replicate the write request data to a destination.

Abstract: A method is provided, comprising: receiving, at a source system, a first copy instruction, the first copy instruction being associated with a token that represents one or more data items, the first copy instruction instructing the source system to copy the one or more data items from a first volume to a second volume; in response to the first copy instruction, retrieving one or more hash digests from a snapshot that is associated with the token, each of the one or more hash digests being associated with a different one of the one or more data items; and transmitting, to a target system, a second copy instruction that is associated with the one or more hash digests, the second copy instruction instructing the target system to copy the one or more data items to a replica of the second volume that is stored at the target system.

Abstract: A method is disclosed for use in a storage system including a source system that is coupled to a target system, the method comprising: detecting a rollback event that is associated with a source volume Vs; and performing a rollback of the source volume Vs in response to the rollback event, wherein performing the rollback of the source volume Vs includes: identifying a target snapset Sr to be rolled back to, the target snapset Sr having a creation time Tr; identifying a snapset recovery pair including a source snapset Sk and a target snapset Sk?, the source snapset having a creation time Ts, and the target snapset having a creation time Tt, such that Tr?Ts?Tt; assigning the source volume Vs to the source snapset Sk; and update the source volume Vs based on a difference between the target snapset Sr and the target snapset Sk?.

Abstract: An apparatus includes at least one processing device, with the at least one processing device being configured, in conjunction with synchronous replication of at least one logical storage volume between first and second storage systems arranged in an active-active configuration, to create a first snapshot of the logical storage volume in the first storage system, to create a second snapshot of the logical storage volume in the second storage system, to create a third snapshot of the logical storage volume in the first storage system, to initiate an asynchronous replication cycle to transfer differential data between the first and the third snapshots in the first storage system to the second storage system, and to utilize the second snapshot and the transferred differential data to create an additional snapshot of the logical storage volume in the second storage system that is synchronized with the third snapshot in the first storage system.

Abstract: An apparatus is configured to initiate a first replication session to replicate data of a first consistency group in a first storage system to a second consistency group in a second storage system, to create an additional consistency group linked to the second consistency group in the second storage system, and to initiate a second replication session to replicate data of the additional consistency group to another consistency group in a third storage system. The additional consistency group linked to the second consistency group in some embodiments is periodically updated against the second consistency group. For example, in one or more embodiments the second consistency group is updated based at least in part on an active snapshot set of the first replication session, and the additional consistency group is updated based at least in part on the second consistency group.

Abstract: A method is used in managing an asynchronous and synchronous transmit priority mechanism. The method receives a plurality of replication requests in conjunction with a replication process, where the plurality of replication requests comprises at least one of a first replication request or a second replication request. A first storage system that comprises a plurality of storage devices is configured to participate in the replication process with a second storage system that comprises a plurality of storage devices. The method optimizes at least one second replication request to optimize processing of the plurality of replication requests.

Abstract: A technique for validating metadata includes creating log entries for virtualization structures pointed to by mapping pointers in a mapping tree and processing the log entries in multiple passes. A current pass validates a current level of redirection and creates new log entries to be processed during a next pass. The new log entries represent a next level of redirection, and as many next passes are processed in sequence as there are next levels of redirection.

Abstract: An aspect of performing on-demand remote snapshot creation for a synchronous replication session between a local system and a remote system of a storage system includes receiving a request for the remote snapshot on the remote system and identifying a current state of the synchronous replication session. The current state is one of a plurality of states. An aspect also includes implementing one or more actions with respect to the remote snapshot as a function of the current state. The actions are performed prior to transitioning from the current state to another state of the plurality of states.

Abstract: An aspect of performing flow control of IO in a synchronous replication session between a local storage and a remote storage of a storage system includes tracking an amount of time an input/output (IO) request is processed at the remote storage including an amount of time the IO request is in transmit to and from the remote storage system. The amount of time indicates a remote latency value. An aspect also includes tracking an amount of time the IO request is processed at the local storage and calculating a difference between the remote latency value and the amount of time the IO request is processed at the local storage. The difference indicates a local latency value. An aspect further includes modifying an amount of IO requests admitted at the storage system as a function of the local latency value.

Abstract: An apparatus includes at least one processing device, with the at least one processing device being configured, in conjunction with synchronous replication of at least one logical storage volume between first and second storage systems arranged in an active-active configuration, to create a first snapshot of the logical storage volume in the first storage system, to create a second snapshot of the logical storage volume in the second storage system, to create a third snapshot of the logical storage volume in the first storage system, to initiate an asynchronous replication cycle to transfer differential data between the first and the third snapshots in the first storage system to the second storage system, and to utilize the second snapshot and the transferred differential data to create an additional snapshot of the logical storage volume in the second storage system that is synchronized with the third snapshot in the first storage system.

Abstract: A method, computer program product, and computer system for receiving, by a computing device, an IO request. It may be determined that data of the IO request includes an indication of an attribute. A prefix descriptor may be constructed for the data in a self-descriptive page buffer based upon, at least in part, determining that the data of the IO request includes the indication of the attribute. An appropriate Application Programming Interface (API) may be called to process the IO request based upon, at least in part, the prefix descriptor.

Abstract: An apparatus is configured to initiate a first replication session to replicate data of a first consistency group in a first storage system to a second consistency group in a second storage system, to create an additional consistency group linked to the first consistency group in the first storage system, and to initiate a second replication session to replicate data of the additional consistency group to another consistency group in a third storage system. The additional consistency group linked to the first consistency group in some embodiments is periodically updated against the first consistency group. For example, in one or more embodiments the second consistency group is updated based at least in part on an active snapshot set of the first replication session, and the additional consistency group is updated based at least in part on the first consistency group.

Abstract: In one aspect, data replication processes include setting a minimum snap set creation interval, a maximum snap set creation interval, and a recovery time threshold (RTT). An aspect further includes creating snap sets during a synchronous replication process based on the snap set creation intervals and the RTT. The snap set creation further includes monitoring an amount of data changes since the last snap set creation, monitoring throughput statistics between a source and target system, and estimating an amount of time to replicate the data changes to the target system based on the data changes and throughput statistics. Upon determining the time to replicate the data changes reaches the RTT and the time since the last snap set creation passes the minimum interval, the snap set creation includes creating a next snap set, storing the next snap set at the source, and replicating the next snap set at the target.