Abstract: Techniques are provided for asynchronous reservation of storage volumes in a storage system with persistent storage of reservation data. One method comprises obtaining, by a target storage device, a reservation command from a host device that requests to reserve a storage volume of the target storage device; creating a new execution thread to process the reservation command, wherein an execution of the reservation command is asynchronous; storing an intermediate result of the reservation command in a persistent storage, wherein the stored intermediate result allows the execution of the reservation command to restart from an execution point following the storage of the intermediate result; and initiating a notification to the host device of the reservation of the storage volume in response to a completion of the execution of the reservation command.

Abstract: A method, computer program product, and computer system for placing, by a computing device, an IO in a Kernel-Endpoint (KE) of a plurality of KEs, wherein the IO may be sent by a host and received in a kernel. The IO in the KE may be pulled from a kernel volume specific handle. The IO may be routed to a corresponding user volume associated with the IO.

Abstract: Techniques for processing commands may include: initially synchronizing a target database of volume reservation and registration information with a source database of volume reservation and registration information; while initially synchronizing the target database with the source database, enabling volume reservation and registration command processing on both a first node managing the source database and a second node managing the target database; while initially synchronizing the target database with the source database, performing first processing to service a first command that is any of a reservation command and a registration command for a first volume; and after initially synchronizing the target database with the source database, using the target database of the second node when servicing reservation and registration commands received at both the first node and the second node.

Abstract: A method, computer program product, and computer system for copying, at a new node, reservation metadata volumes of an old node. While a software upgrade is in progress, volume reservation command processing may be enabled on both the new node and the old node when copying is complete. Separate logic may be run to process a volume reservation command of the volume reservation command processing. The old node may be switched to a primary mode, wherein the new node may be switched to a secondary mode to synchronize volume reservation metadata with a primary copy. When the software upgrade is complete, the new node may be switched to a single mode to use only a volume reservation database of the new node.

Abstract: Techniques are provided for asynchronous reservation of storage volumes in a storage system with persistent storage of reservation data. One method comprises obtaining, by a target storage device, a reservation command from a host device that requests to reserve a storage volume of the target storage device; creating a new execution thread to process the reservation command, wherein an execution of the reservation command is asynchronous; storing an intermediate result of the reservation command in a persistent storage, wherein the stored intermediate result allows the execution of the reservation command to restart from an execution point following the storage of the intermediate result; and initiating a notification to the host device of the reservation of the storage volume in response to a completion of the execution of the reservation command.

Abstract: A simulated stretched volume may be configured from multiple volumes of a single data storage system. The volumes may be assigned unique identifiers. The volumes may be exposed to a host over paths from the single data storage system as the same volume having the same unique identifier. The single data storage system may include sets of target ports with each set simulating paths to a different data storage system. A management command may be received that is directed to the simulated stretched volume having the unique identifier. The management command may be received on a path from the host to a target port of the single data storage system. Servicing the management command may include the single data storage system simulating either the local or remote system depending on the set of target ports including the target port.

Abstract: A method for use in a storage system is disclosed, comprising: receiving, at a first server in the storage system, a given block layer request for reservation of a storage resource, by the first server, an identifier corresponding to the given block layer request; performing a search of a database to detect whether the given block layer request has been completed, the search being performed by the first server, the search being performed based on the identifier corresponding to the given block layer request; when the database indicates that the given block layer request has not been completed: completing the given block layer request and transmitting a notification that the given block layer request is completed; and when the database indicates that given block layer request has been completed, re-transmitting a notification that the given block layer request is completed.

Abstract: Techniques for processing commands may include: initially synchronizing a target database of volume reservation and registration information with a source database of volume reservation and registration information; while initially synchronizing the target database with the source database, enabling volume reservation and registration command processing on both a first node managing the source database and a second node managing the target database; while initially synchronizing the target database with the source database, performing first processing to service a first command that is any of a reservation command and a registration command for a first volume; and after initially synchronizing the target database with the source database, using the target database of the second node when servicing reservation and registration commands received at both the first node and the second node.

Abstract: A method, computer program product, and computing system for generating, at a first storage appliance of a plurality of storage appliances, a first volume that is configured to be managed by the first storage appliance, wherein data within the first volume is accessible by the first storage appliance. In response to generating the first volume, a protocol identifier representation of the first volume may be generated at each other storage appliance of the plurality of storage appliances and may be configured to be managed by a respective storage appliance of the plurality of storage appliances.

Abstract: A method, computer program product, and computer system for copying, at a new node, reservation metadata volumes of an old node. While a software upgrade is in progress, volume reservation command processing may be enabled on both the new node and the old node when copying is complete. Separate logic may be run to process a volume reservation command of the volume reservation command processing. The old node may be switched to a primary mode, wherein the new node may be switched to a secondary mode to synchronize volume reservation metadata with a primary copy. When the software upgrade is complete, the new node may be switched to a single mode to use only a volume reservation database of the new node.

Abstract: A method, computer program product, and computer system for placing, by a computing device, an IO in a Kernel-Endpoint (KE) of a plurality of KEs, wherein the IO may be sent by a host and received in a kernel. The IO in the KE may be pulled from a kernel volume specific handle. The IO may be routed to a corresponding user volume associated with the IO.

Abstract: A simulated stretched volume may be configured from multiple volumes of a single data storage system. The volumes may be assigned unique identifiers. The volumes may be exposed to a host over paths from the single data storage system as the same volume having the same unique identifier. The single data storage system may include sets of target ports with each set simulating paths to a different data storage system. A management command may be received that is directed to the simulated stretched volume having the unique identifier. The management command may be received on a path from the host to a target port of the single data storage system. Servicing the management command may include the single data storage system simulating either the local or remote system depending on the set of target ports including the target port.

Abstract: A method, computer program product, and computer system for maintaining a federation of a plurality of appliances as a single subsystem, wherein maintaining the federation as the single subsystem may include maintaining a centralized discovery mechanism across the plurality of appliances, wherein a discovery service of the centralized discovery mechanism may return a list of all ports in the federation. Controller IDs for a predefined range of controller IDs may be allocated for a plurality of dynamic controllers per appliance of the plurality of appliances, wherein the controller IDs may be allocated as a response to a connect command from a host. An empty namespace list for the plurality of dynamic controllers on the plurality of appliances in the federation may be exposed. The host may receive a notification from at least one dynamic controller of the plurality of dynamic controllers on at least one appliance of the plurality of appliances in the federation.

Abstract: A method, computer program product, and computing system for generating, at a first storage appliance of a plurality of storage appliances, a first volume that is configured to be managed by the first storage appliance, wherein data within the first volume is accessible by the first storage appliance. In response to generating the first volume, a protocol identifier representation of the first volume may be generated at each other storage appliance of the plurality of storage appliances and may be configured to be managed by a respective storage appliance of the plurality of storage appliances.

Abstract: A method, computer program product, and computer system for maintaining a federation of a plurality of appliances as a single subsystem, wherein maintaining the federation as the single subsystem may include maintaining a centralized discovery mechanism across the plurality of appliances, wherein a discovery service of the centralized discovery mechanism may return a list of all ports in the federation. Controller IDs for a predefined range of controller IDs may be allocated for a plurality of dynamic controllers per appliance of the plurality of appliances, wherein the controller IDs may be allocated as a response to a connect command from a host. An empty namespace list for the plurality of dynamic controllers on the plurality of appliances in the federation may be exposed. The host may receive a notification from at least one dynamic controller of the plurality of dynamic controllers on at least one appliance of the plurality of appliances in the federation.

Abstract: Migrating a source volume from a source appliance to a destination appliance, wherein the source volume is assigned to an asymmetric namespace access (ANA) group and initially exposed to a host computer as accessible at the source appliance, includes creating a destination volume on the destination appliance and expanding the ANA group to include the destination volume, with the ANA group initially exposing the destination volume as inaccessible to the host computer at the destination appliance. Subsequently, the destination volume is synchronized to the source volume and then a cutover is performed that includes (i) copying volume metadata including host reservations from the source volume to the destination volume, and (ii) changing the ANA group to expose the source volume as inaccessible at the source appliance and the destination volume as accessible at the destination appliance.

Abstract: A method for use in a storage system is disclosed, comprising: receiving, at a first server in the storage system, a given block layer request for reservation of a storage resource, by the first server, an identifier corresponding to the given block layer request; performing a search of a database to detect whether the given block layer request has been completed, the search being performed by the first server, the search being performed based on the identifier corresponding to the given block layer request; when the database indicates that the given block layer request has not been completed: completing the given block layer request and transmitting a notification that the given block layer request is completed; and when the database indicates that given block layer request has been completed, re-transmitting a notification that the given block layer request is completed.