Abstract: A node mask of a global metadata structure entry representing an MD portion in GM may be updated when an entry of a local MD table representing the MD portion is removed in response to receiving an IO operation, without negatively impacting performance of the IO operation. An update process that is independent of the process executing the IO operation may update the node mask so that performance of the IO operation is not negatively affected. In response to the entry for the MD portion being removed from the local MD table, an entry may be added to a queue. The update process may include accessing the entries in the queue, and, for each entry, updating the node mask (e.g., clearing a bit representing the processing node) and removing the entry from the queue.

Abstract: Data protection operations based on direct storage access. Data protection operations that involve large data transfers are optimized or improved by transferring the data using a communication path that includes direct access to disks of a storage array. This avoids latencies associated with transferring data through the layers of the storage array. The locations of the data to be transferred are identified and provided to an appliance. The appliance can then read and transfer the data over a communication path that includes direct disk access.

Abstract: Data protection operations based on direct storage access. Data protection operations that involve large data transfers are optimized or improved by transferring the data using a communication path that includes direct access to disks of a storage array. This avoids latencies associated with transferring data through the layers of the storage array. The locations of the data to be transferred are identified and provided to an appliance. The appliance can then read and transfer the data over a communication path that includes direct disk access.

Abstract: A host system performs I/O processing using metadata for a storage system, where none or some of the metadata is stored on the host system. The host system may be coupled to the global memory of the storage system along a communication path that includes an internal switching fabric of the storage system and does not include a network located externally to the storage system. The host system may exchange communications over the communication path to access indirection layers on the storage system to determine a global memory address of metadata corresponding to an I/O operation. The host system may include a host metadata table of global memory addresses for metadata of logical locations logical devices. The host system may query the host metadata table for a global memory address of metadata corresponding to a logical location specified in an I/O operation.

Abstract: Data protection operations based on direct storage access. Data protection operations that involve large data transfers are optimized or improved by transferring the data using a communication path that includes direct access to disks of a storage array. This avoids latencies associated with transferring data through the layers of the storage array. The locations of the data to be transferred are identified and provided to an appliance. The appliance can then read and transfer the data over a communication path that includes direct disk access.

Abstract: A node mask of a global metadata structure entry representing an MD portion in GM may be updated when an entry of a local MD table representing the MD portion is removed in response to receiving an IO operation, without negatively impacting performance of the IO operation. An update process that is independent of the process executing the IO operation may update the node mask so that performance of the IO operation is not negatively affected. In response to the entry for the MD portion being removed from the local MD table, an entry may be added to a queue. The update process may include accessing the entries in the queue, and, for each entry, updating the node mask (e.g., clearing a bit representing the processing node) and removing the entry from the queue.

Abstract: Systems and methods for scheduling multiple flows in a computing system or for allocating resources to the flows in the computing system. Each flow may be associated with a target priority and a target performance. A current priority can be determined for each flow and resources are allocated based on the highest current priority. Over time, the current priorities change and each flow will receive resources as the flows are scheduled for execution. No flow is starved of resources.

Abstract: Physical storage devices may be managed for spontaneous de-staging from a cache, for example, by determining a background task threshold (UBTT), and controlling one or more physical storage devices to use the UBTT instead of the VBTT in determining when to enter background task mode. The determined UBTT may be less than the VBTT, which may cause the physical storage device to enter into background task mode earlier, which means that background tasks like garbage collection and write leveling may be performed more frequently. An ability to turn on and turn off management of physical storage devices for spontaneous de-staging of a cache may be provided. It may be desirable to turn off physical storage device management for spontaneous de-staging, for example, during peak workload hours, to prevent physical storage devices from entering into background task mode more frequently during certain times.

Abstract: A host system performs I/O processing using metadata for a storage system, where none or some of the metadata is stored on the host system. The host system may be coupled to the global memory of the storage system along a communication path that includes an internal switching fabric of the storage system and does not include a network located externally to the storage system. The host system may exchange communications over the communication path to access indirection layers on the storage system to determine a global memory address of metadata corresponding to an I/O operation. The host system may include a host metadata table of global memory addresses for metadata of logical locations logical devices. The host system may query the host metadata table for a global memory address of metadata corresponding to a logical location specified in an I/O operation.

Abstract: Physical storage devices may be managed for spontaneous de-staging from a cache, for example, by determining a background task threshold (UBTT), and controlling one or more physical storage devices to use the UBTT instead of the VBTT in determining when to enter background task mode. The determined UBTT may be less than the VBTT, which may cause the physical storage device to enter into background task mode earlier, which means that background tasks like garbage collection and write leveling may be performed more frequently. An ability to turn on and turn off management of physical storage devices for spontaneous de-staging of a cache may be provided. It may be desirable to turn off physical storage device management for spontaneous de-staging, for example, during peak workload hours, to prevent physical storage devices from entering into background task mode more frequently during certain times.

Abstract: Systems and methods for scheduling multiple flows in a computing system or for allocating resources to the flows in the computing system. Each flow may be associated with a target priority and a target performance. A current priority can be determined for each flow and resources are allocated based on the highest current priority. Over time, the current priorities change and each flow will receive resources as the flows are scheduled for execution. No flow is starved of resources.

Abstract: In one aspect, a method includes receiving a read or write command from a requester to read data from or write data to a database, inserting in a status message on a status of the read or write command an identifier to identify technology of storage for the data and providing the status message associated with the read or write command to the requester.

Abstract: Efficiently storing low priority data in high priority storage devices is described. A system receives a request from an application to store a data chunk received from the application. The system determines a priority of the application. The system executes a write command to store the data chunk to a high priority storage device. If the application is low priority and the identifier of the received data chunk is a duplicate of any of the identifiers of the data chunks that were previously stored in the high priority storage device, the system stores, into the high priority storage device, the received data chunk as a low priority reference to a data chunk that was previously stored in the high priority storage device.

Abstract: In one aspect, a method includes receiving a read or write command from a requester to read data from or write data to a database, inserting in a status message on a status of the read or write command an identifier to identify technology of storage for the data and providing the status message associated with the read or write command to the requester.