Abstract: A storage system in one embodiment is configured to participate as a source storage system in a synchronous replication process with a target storage system. In conjunction with the synchronous replication process, the source storage system receives write requests from at least one host device. Responsive to a given write request being a multi-page write request, an entry is created in a first journal, where the first journal is utilized to ensure that the given write request is completed for all of the pages or for none of the pages. Responsive to the write request being a single-page write request, an entry is created in a second journal different than the first journal. An address-to-signature table is updated utilizing write data of the write request, and if the corresponding entry for the write request was created in the first journal, the entry is swapped from the first journal into the second journal, and the write data of the write request is sent to the target storage system.

Abstract: Example embodiments of the present invention relate to methods, systems, and computer program products for determining replicas for removal from a plurality of replicas as defined in a data retention policy. The method includes performing asynchronous replication from a source to a target according to time-based replication cycles. A retention policy then may be identified defining a number of asynchronous replication replicas to retain and a plurality of associated periods which then may be retained according to the policy.

Abstract: A processing device stores a first log entry in a first log structure that stores log entries regarding occurrences of events for a first core in a computer system composed of a plurality of cores. In response to detecting the occurrence of a log flush trigger event, the processing device copies a plurality of log entries, including the first log entry, from the first log structure as a second log entry in a second log structure that stores log entries for multiple of the plurality of cores. The processing device dynamically determines the size of the second log entry based on the varied sizes of the plurality of log entries. The processing device generates a log entry header for the second log entry, including at least a core identifier identifying the first core associated with the first log structure and prepends the log entry header to the second log entry.

Abstract: An apparatus in one embodiment comprises a host device that includes at least one processor and an associated memory. The host device is configured to implement a plurality of containers each configured to access one or more portions of the memory. The containers are implemented as respective kernel control groups utilizing operating system level virtualization of the processor of the host device. The host device is further configured to assign the containers to groups in accordance with one or more designated criteria, and to generate checkpoints for respective groups of the containers. In conjunction with generation of a given one of the checkpoints for a particular one of the groups of containers, the host device identifies one or more pages of the memory that are shared by at least first and second containers of the particular group of containers, and generates the given checkpoint without duplicating the one or more shared pages to persistent storage.

Abstract: A processing device stores a first log entry in a first log structure that stores log entries regarding occurrences of events for a first core in a computer system composed of a plurality of cores. In response to detecting the occurrence of a log flush trigger event, the processing device copies a plurality of log entries, including the first log entry, from the first log structure as a second log entry in a second log structure that stores log entries for multiple of the plurality of cores. The processing device dynamically determines the size of the second log entry based on the varied sizes of the plurality of log entries. The processing device generates a log entry header for the second log entry, including at least a core identifier identifying the first core associated with the first log structure and prepends the log entry header to the second log entry.

Abstract: A first storage system is configured to participate in a replication process with a second storage system. The first and second storage systems initially operate in an asynchronous replication mode and subsequently transition to a synchronous replication mode. The first and second storage systems concurrently operate in both modes for at least a portion of the transition. While the first and second storage systems are concurrently operating in both modes, the first storage system is configured to detect a given data page that has been subject to one or more write operations in the first storage system since generation of a corresponding set of one or more snapshots for a most recent data transfer cycle of the asynchronous replication mode, to initiate a data transfer request for the given data page, and to update a content-based signature of the given data page. The second storage system determines whether to accept or reject the transfer of the given data page.

Abstract: Example embodiments of the present invention relate to methods, systems, and computer program products for determining replicas for removal from a plurality of replicas as defined in a data retention policy. The method includes performing asynchronous replication from a source to a target according to time-based replication cycles. A retention policy then may be identified defining a number of asynchronous replication replicas to retain and a plurality of associated periods which then may be retained according to the policy.

Abstract: A system, computer program product, and computer-executable method of optimizing replication between a first Content Addressable Storage (CAS) system and a second CAS system, the system, computer program product, and computer-executable method including analyzing the first CAS system and the second CAS system to determine an amount of differences between the first CAS system and the second CAS system, upon determining that the amount of differences are below a threshold amount, sending a set of replication information to the second CAS system, wherein the set of information includes a first address and a first hash for a portion of data stored on the first CAS system, analyzing, at the second CAS system, the set of replication information to determine whether to request that the first CAS system send data associated with the set of replication information; upon a negative determination, sending the data associated with the set of replication information.

Abstract: A system, computer program product, and computer-executable method of providing a layout-independent cryptographic stamp of a distributed data set from a data storage system, the system, computer program product, and computer-executable method comprising receiving a request for a cryptographic stamp of the distributed data set, creating a hash of each slice of the distributed data set, and using each hash from each slice of the distribute data set to create the cryptographic stamp of the distributed data set.

Abstract: Example embodiments of the present invention relate to methods, systems, and a computer program product for performing asynchronous replication of a snapshot. The method includes assigning a unique identifier to a snapshot at a source node in a data storage system. Asynchronous replication of the snapshot, including the unique identifier, then may be performed from the source node to a target node. Integrity of the replicated snapshot having the unique identifier then may be verified at the target node.

Abstract: Example embodiments of the present invention relate to methods, systems, and computer program products for determining replicas for removal from a plurality of replicas. The method includes identifying a set of user conditions associated with time windows as defined in a data retention policy. The method further includes, for each user condition, determining a plurality of replicas satisfying the user condition having a time value in the associated time window and, if the plurality of replicas exceeds a maximum for the user condition as defined in the data retention policy, removing extraneous replicas from the plurality of replicas so the plurality of replicas does not exceed the maximum for the user condition.

Abstract: An apparatus in one embodiment comprises a host device that includes at least one processor and an associated memory. The host device is configured to implement a plurality of processes each configured to access a shared region of the memory. The host device is further configured to establish a multi-process control group for the shared region, to maintain state information for the multi-process control group, and to track usage of the shared region by the processes based at least in part on the state information. At least a subset of the processes may comprise respective containers implemented utilizing operating system level virtualization of the processor of the host device. The multi-process control group established for the shared region illustratively comprises a coarse-grained control group having a granularity greater than a single page of the shared region.

Abstract: A storage system in one embodiment comprises a plurality of storage devices and a storage controller. The storage system implements a loopback replication process in which one or more source storage objects are replicated to one or more corresponding target storage objects within the storage system. The storage system obtains a pairing identifier, pairs a source storage object with a target storage object by associating respective distinct instances of the pairing identifier with the source storage object and the target storage object, and replicates the source storage object to the target storage object based at least in part on the associated instances of the pairing identifier. Each of the source and target instances of the pairing identifier comprises a collision field. The collision fields of the source and target instances of the pairing identifier have respective distinct values in order to prevent collisions between the source and target storage objects during loopback replication.

Abstract: A storage system in one embodiment comprises a plurality of storage devices and a storage controller. The storage system is configured to implement a loopback replication process in which one or more source storage objects are replicated to one or more corresponding target storage objects within the storage system. The storage system is further configured to divide a storage space provided by at least portions of the storage devices of the storage system into slices, to subdivide the slices into source slices and target slices, and to replicate a source storage object associated with at least one of the source slices to a target storage object associated with at least one of the target slices. The source storage object may be associated with at least one of the source slices by, for example, storing the source storage object across portions of the storage devices in designated ones of the source slices.

Abstract: A first storage system in one illustrative embodiment is configured to participate in a replication process with a second storage system. The first storage system detects a replication failure condition or other condition requiring termination of a synchronous replication mode of the replication process, and responsive to the detected condition, captures a snapshot of source data that is subject to replication from the first storage system to the second storage system as part of the replication process. The first storage system terminates the synchronous replication mode of the replication process, initiates an asynchronous replication mode of the replication process, executes an asynchronous-to-synchronous transition cycle scan operation for the replication process utilizing the captured snapshot, and resumes the synchronous replication mode of the replication process responsive to successful completion of the asynchronous-to-synchronous transition cycle scan operation.

Abstract: Described embodiments provide systems and methods for low disk space notification. Data modules maintain space usage counters for normal stripes and for checkpoint stripes. The data modules also monitor in use space counters; free space counters; and checkpoint space counters. A system wide total space is calculated, as well as in use space, free space and checkpoint space by aggregating worst case space usage from all data modules. A checkpoint free space ratio and an overall system free space ratio are determined and a checkpoint notification is triggered when the checkpoint free space ratio is lower than a first threshold or when the overall system free space ratio is lower than a second threshold. Upon a checkpoint notification being triggered, a checkpoint notification handling routine is executed to free up disk space.

Abstract: Described embodiments provide systems and methods for online system recovery orchestration. Embodiments may include receiving a request to recover a system management process from a checkpoint. The system management initialization parameter file is updated by setting a flag to start from the checkpoint. A system management process is started with the updated initialization parameter and a copy of the system management repository is loaded. Volumes are recovered before data path module activation. Data modules are then activated with checkpoint offset information and data module journals are reformatted. Control modules are then activated with recovered volume configuration and control module journals are reformatted. Defragmentation mode is set to rollback mode and data on checkpoint stripes that were written after checkpoint creation are deleted. After waiting for the defragmentation rollback to complete the host IO direction is set to checkpoint stripes.

Abstract: A target storage system in one embodiment receives from a source storage system a plurality of content-based signatures of respective data pages of a storage object that is subject to replication from the source storage system to the target storage system. For a given one of the received content-based signatures having a particular logical address, the target storage system compares at least a portion of the received content-based signature with a particular one of a plurality of entries of an address-to-signature table maintained by the target storage system.

Abstract: A system, computer program product, and computer-executable method of providing a layout-independent cryptographic stamp of a distributed data set from a data storage system, the system, computer program product, and computer-executable method comprising receiving a request for a cryptographic stamp of the distributed data set, creating a hash of each slice of the distributed data set, and using each hash from each slice of the distribute data set to create the cryptographic stamp of the distributed data set.

Abstract: Virtual storage domains (VSD) are each associated with unique VSD domain ID associated with a first policy and tagged to a request to a storage system when an entity writes a data set to it. A first hash digest, based on data set content, is calculated and combined with first unique VSD domain ID into a second hash digest associated with data set. When first policy is changed to second policy associated with second VSD, a third hash digest of first data set is calculated, the third hash digest based on content of first data set and on second unique VSD domain ID. If third hash digest does not exist in second VSD, data set is copied to the second VSD; else, reference count of the third hash digest, associated with second VSD domain, is incremented, and reference count of second hash digest, associated with first VSD domain, is decremented.