Abstract: A technique improves implementation of an index for an operations log (oplog) that coalesces random write operations directed to a virtual disk (vdisk) stored on an extent store. The oplog temporarily caches data associated with the random write operations (i.e., write data) as well as metadata describing the write data. The metadata includes descriptors to the write data stored on virtual address regions, i.e., offset ranges, of the vdisk and are used to identify the offset ranges of write data for the vdisk that are cached in the oplog. To facilitate fast lookup operations of the offset ranges when determining whether write data is cached in the oplog, an oplog index provides a state of the latest data for offset ranges of the vdisk. The technique improves implementation of the oplog index by storing the oplog index in storage class memory, such as persistent memory, to obviate failure and subsequent recovery of the oplog index.

Abstract: A technique monitors input/output (I/O) and Persistent Reservation (PR) activity patterns to detect degraded performance of a highly available and fault tolerant application executing in a multi-site disaster recovery (DR) environment. Multiple instances of the application execute in different virtual machines (VMs) of a compute layer within a guest clustering configuration that extends across clusters of the sites. A storage layer of the clusters provides shared storage to the multiple VMs across the multiple sites. One of the sites is configured as an active storage site configured to receive and service I/O requests from the compute layer. A single instance of the application is active at a time and configured as a “compute owner” of the shared storage to issue the I/O requests to the shared storage. The compute owner and active storage site may not be co-located on the same site, leading to excessive I/O and PR activity patterns indicative of degraded performance.

Abstract: Methods, systems, and computer program products for moving a container-based application from a source HCI cluster to a target HCI cluster. An HCI storage cluster data replication mechanism operates to copy data and metadata from a plurality of storage devices that constitute a storage pool of the source HCI cluster. A container-based application replication mechanism operates to copy data and metadata from an executable container that is running on a node of the source HCI cluster. Periodically (1) the state of the container-based application is saved using the container-based application replication mechanism, and (2) the state of the storage cluster data of the HCI storage cluster is saved using the HCI storage cluster data replication mechanism. The saved state of the container-based application including its application data and metadata are combined with the saved state of the storage cluster data to bring-up the container-based application at the target HCI cluster.

Abstract: Label-based replication of data between two computing clusters. A replication session is established between a source cluster and a target cluster. After making a data item status inquiry originating from the source cluster, the target cluster assesses its then-current status of the data item. Based at least in part on the target cluster's then-current status of the data item, the source cluster determines that at least a portion of the data item can be streamed from the source cluster to the target cluster. As such, rather than making further inquiries to the target cluster as pertains to constituent contents of the data item, the constituent contents of the data item are sent to the target without incurring the protocol costs of making further inquiries. The target cluster determines its then-current status of the data item based on a data item label taken from an entry of a cluster data manifest.

Abstract: A technique replicates an index of an operations log (oplog) from a primary node to a secondary node of a cluster in the event of failure. The oplog functions as a staging area to coalesce random write operations directed to a virtual disk (vdisk) stored on a backend storage tier. The oplog temporarily caches write data as well as metadata describing the write data. The metadata includes descriptors to the write data corresponding to offset ranges of the vdisk and are used to identify ranges of write data for the vdisk that are cached in the oplog. To facilitate fast lookup operations of whether write data is cached in the oplog, an oplog index provides a state of the latest data for offset ranges of the vdisk that enables fast failover of metadata used to construct the oplog index in memory without downtime or significant metadata replay.

Abstract: A dynamic feedback technique improves data replication performance by balancing rates of data retrieval and data transmission of a fragmented virtual disk replicated between nodes of clusters on a local site and a remote site of a disaster recovery environment. Each node is embodied as a physical computer with hardware resources, such as processor, memory, network and storage resources, which are virtualized to provide support for one or more user virtual machines executing on the node. The storage resources include storage devices of an extent store, whereas the network includes a wide area network connecting the local and remote sites. The dynamic feedback technique employs a virtual memory buffer configured to balance the data storage retrieval and network transmission rates at a source of replication based on bandwidth demands of the extent store and network throughput as manifested by an available free space (i.e., emptiness) of the virtual buffer.

Abstract: Methods, systems, and computer program products for moving a container-based application from a source HCl cluster to a target HCl cluster. An HCl storage cluster data replication mechanism operates to copy data and metadata from a plurality of storage devices that constitute a storage pool of the source HCl cluster. A container-based application replication mechanism operates to copy data and metadata from an executable container that is running on a node of the source HCl cluster. Periodically (1) the state of the container-based application is saved using the container-based application replication mechanism, and (2) the state of the storage cluster data of the HCl storage cluster is saved using the HCl storage cluster data replication mechanism. The saved state of the container-based application including its application data and metadata are combined with the saved state of the storage cluster data to bring-up the container-based application at the target HCl cluster.

Abstract: Methods, systems, and computer program products for moving a container-based application from a source HCI cluster to a target HCI cluster. An HCI storage cluster data replication mechanism operates to copy data and metadata from a plurality of storage devices that constitute a storage pool of the source HCI cluster. A container-based application replication mechanism operates to copy data and metadata from an executable container that is running on a node of the source HCI cluster. Periodically (1) the state of the container-based application is saved using the container-based application replication mechanism, and (2) the state of the storage cluster data of the HCI storage cluster is saved using the HCI storage cluster data replication mechanism. The saved state of the container-based application including its application data and metadata are combined with the saved state of the storage cluster data to bring-up the container-based application at the target HCI cluster.

Abstract: A technique improves implementation of an index for an operations log (oplog) that coalesces random write operations directed to a virtual disk (vdisk) stored on an extent store. The oplog temporarily caches data associated with the random write operations (i.e., write data) as well as metadata describing the write data. The metadata includes descriptors to the write data stored on virtual address regions, i.e., offset ranges, of the vdisk and are used to identify the offset ranges of write data for the vdisk that are cached in the oplog. To facilitate fast lookup operations of the offset ranges when determining whether write data is cached in the oplog, an oplog index provides a state of the latest data for offset ranges of the vdisk. The technique improves implementation of the oplog index by storing the oplog index in storage class memory, such as persistent memory, to obviate failure and subsequent recovery of the oplog index.

Abstract: A technique replicates an index of an operations log (oplog) from a primary node to a secondary node of a cluster in the event of a failure of the primary node. The oplog functions as a staging area to coalesce random write operations directed to a virtual disk (vdisk) stored on a backend storage tier organized as an extent store. The oplog temporarily caches data associated with the random write operations (i.e., write data) as well as metadata describing the write data. The metadata includes descriptors to the write data corresponding to virtual address regions, i.e., offset ranges, of the vdisk and are used to identify the offset ranges of write data for the vdisk that are cached in the oplog. To facilitate fast lookup operations of the offset ranges when determining whether write data io is cached in the oplog, an oplog index provides a state of the latest data for offset ranges of the vdisk.

Abstract: A dynamic feedback technique improves data replication performance by balancing rates of data retrieval and data transmission of a fragmented virtual disk replicated between nodes of clusters on a local site and a remote site of a disaster recovery environment. Each node is embodied as a physical computer with hardware resources, such as processor, memory, network and storage resources, which are virtualized to provide support for one or more user virtual machines executing on the node. The storage resources include storage devices of an extent store, whereas the network includes a wide area network connecting the local and remote sites. The dynamic feedback technique employs a virtual memory buffer configured to balance the data storage retrieval and network transmission rates at a source of replication based on bandwidth demands of the extent store and network throughput as manifested by an available free space (i.e., emptiness) of the virtual buffer.

Abstract: Improved techniques and systems are disclosed for ensuring that physical storage is available for cached allocating writes in a thinly provisioned storage environment. By monitoring the size of the cached allocating writes in the file system cache and taking cache occupancy reduction actions when criteria for cache reduction are fulfilled, caching of allocating writes that do not have a corresponding physical storage allocation can be eliminated or reduced to a user-configurable maximum without disabling caching of allocating writes. Using these techniques, allocating writes may be cached without risk of data loss.

Abstract: Techniques for storage network bandwidth management are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method for storage network bandwidth management comprising sampling, using at least one computer processor, application Input/Output (I/O) requests associated with the unit of storage during a specified period of time, determining a maximum latency value based on the sampling of the application Input/Output (I/O) requests, comparing the maximum latency value with a current latency value, and throttling administrative I/O requests in the event that the current latency value exceeds the maximum latency value.

Abstract: A method, system, and computer readable medium for asynchronously processing write operation on a volume having copy-on-write snapshots. In one embodiment, the method comprises the steps of: updating a normal mirror with write data associated with a write operation for the volume; asynchronously copying the write data from an asynchronous mirror to at least one copy-on-write snapshot; and, once the at least one copy-on-write snapshot is updated, updating the asynchronous mirror with the write data from the normal mirror.

Abstract: A method, system, and computer readable medium for asynchronously processing write operation on a volume having copy-on-write snapshots. In one embodiment, the method comprises the steps of: updating a normal mirror with write data associated with a write operation for the volume; asynchronously copying the write data from an asynchronous mirror to at least one copy-on-write snapshot; and, once the at least one copy-on-write snapshot is updated, updating the asynchronous mirror with the write data from the normal mirror.

Abstract: A method and apparatus for accessing a virtualized storage volume are described. At least one volume map is copied to a virtualization switch prior to an application requesting access to a storage volume via the virtualization switch, where the volume map facilitates mapping the storage volume access request to an appropriate physical storage device and is copied from a source external to the virtualization switch.

Abstract: A method, system, and computer readable medium for maintaining the order of write-commands issued to a data storage, where the write-commands are issued by one or more host. In one embodiment of the present invention the method includes assigning an order-descriptor to each write-command, storing the write-command, storing the order-descriptor, and collating a plurality of order-descriptors and their corresponding write-commands to obtain an ordered write-command stream.