Abstract: An apparatus for dynamically adjusting a journal snapshot window is disclosed. A computer-implemented method and computer program product also perform the functions of the apparatus. According to an embodiment of the present invention, a failure detection module detects a potential failure of at least a portion of a non-volatile storage device. The non-volatile storage device includes a journal for tracking metadata changes for data that is stored on the non-volatile storage device prior to committing the metadata changes to metadata for the non-volatile storage device. A notification receiving module receives an indication of the potential failure of the non-volatile storage device. A snapshot module adjusts a snapshot window for the journal in response to the indication of the potential failure. The snapshot window includes a set of metadata changes in the journal that have not been committed to the metadata of the non-volatile storage device.

Abstract: Method and system are provided for storage handling guidance for host input/output (I/O) operations. The method includes: providing a guidance array of indications of storage operations handling instructions, the guidance array having multiple dimensions of performance characteristics with each dimension having multiple levels; and associating a reference vector with one or more I/O operations, wherein the reference vector points to a level for each dimension of the array to obtain an indication of a storage operations handling instruction at an intercept of the dimension levels for application by a storage system controller for the one or more I/O operations.

Abstract: Method and system are provided for data validation during data recovery in a log-structure array (LSA) storage system. The method includes reading a log record of a recovery log for a logical address to obtain a physical address at a storage backend for the data at the time of the log record; reading reference metadata at the obtained physical address, wherein the reference metadata indicates the logical address that last wrote data to the physical address; validating that the physical address for the log record contains valid data for the logical address of the log record by comparing the logical address of the reference metadata to the logical address of the log record; and replaying the log record if the physical address is validated for recovery of virtual domain logical metadata mapping the logical address to the physical addresses of the log record.

Abstract: An apparatus for dynamically adjusting a journal snapshot window is disclosed. A computer-implemented method and computer program product also perform the functions of the apparatus. According to an embodiment of the present invention, a failure detection module detects a potential failure of at least a portion of a non-volatile storage device. The non-volatile storage device includes a journal for tracking metadata changes for data that is stored on the non-volatile storage device prior to committing the metadata changes to metadata for the non-volatile storage device. A notification receiving module receives an indication of the potential failure of the non-volatile storage device. A snapshot module adjusts a snapshot window for the journal in response to the indication of the potential failure. The snapshot window includes a set of metadata changes in the journal that have not been committed to the metadata of the non-volatile storage device.

Abstract: Method and system are provided for data validation during data recovery in a log-structure array (LSA) storage system. The method includes reading a log record of a recovery log for a logical address to obtain a physical address at a storage backend for the data at the time of the log record; reading reference metadata at the obtained physical address, wherein the reference metadata indicates the logical address that last wrote data to the physical address; validating that the physical address for the log record contains valid data for the logical address of the log record by comparing the logical address of the reference metadata to the logical address of the log record; and replaying the log record if the physical address is validated for recovery of virtual domain logical metadata mapping the logical address to the physical addresses of the log record.

Abstract: Method and system are provided for storage handling guidance for host input/output (I/O) operations. The method includes: providing a guidance array of indications of storage operations handling instructions, the guidance array having multiple dimensions of performance characteristics with each dimension having multiple levels; and associating a reference vector with one or more I/O operations, wherein the reference vector points to a level for each dimension of the array to obtain an indication of a storage operations handling instruction at an intercept of the dimension levels for application by a storage system controller for the one or more I/O operations.

Abstract: Embodiments of the present invention disclose a method, a computer program product, and a computer system for data synchronization. A first data storage device reads a first data region and generates a first hash of the first data region before transmitting the first hash to a second data storage device. The second data storage device reads a second data region corresponding to the first data region and generates a second hash of the second data region. The second data storage device then determines whether the first hash matches the second hash and, based on determining that the first hash does not match the second hash, transmits data of the second data region to the first data storage device. The first data storage device applies the data of the second data region, thereby synchronizing the first data storage device and the second data storage device.

Abstract: A computer-implemented method of storing data on a storage device can receive an I/O request to read data from or write data to a data storage device. The data can be stored in special sectors as allocated sectors and regular sectors as a log-structured array (LSA). If the I/O request is to read data from the storage device, a determination can be made as to whether the data to be read is stored as a special sector, which can be read from the LSA, or as a regular sector, which can be can be read from the allocated sectors. If the I/O request is to write data to the storage device, a determination can be made as to whether the data to be written is stored as a special sector, to the LSA or as a regular sector, to the allocated sectors.

Abstract: A computer-implemented method of storing data on a storage device can receive an I/O request to read data from or write data to a data storage device. The data can be stored in special sectors as allocated sectors and regular sectors as a log-structured array (LSA). If the I/O request is to read data from the storage device, a determination can be made as to whether the data to be read is stored as a special sector, which can be read from the LSA, or as a regular sector, which can be can be read from the allocated sectors. If the I/O request is to write data to the storage device, a determination can be made as to whether the data to be written is stored as a special sector, to the LSA or as a regular sector, to the allocated sectors.

Abstract: Embodiments of the present invention disclose a method, a computer program product, and a computer system for data synchronization. A first data storage device reads a first data region and generates a first hash of the first data region before transmitting the first hash to a second data storage device. The second data storage device reads a second data region corresponding to the first data region and generates a second hash of the second data region. The second data storage device then determines whether the first hash matches the second hash and, based on determining that the first hash does not match the second hash, transmits data of the second data region to the first data storage device. The first data storage device applies the data of the second data region, thereby synchronizing the first data storage device and the second data storage device.

Abstract: A multi-node data storage system comprises a first data storage system having an owner node and a backup node in a first location coupled to a second data storage system having an owner node and a backup node in a second location. Each storage system includes a copy of the same data volume. A failure of a node of the multi-node storage system is detected. An outstanding write request to the first storage system is identified. If the owner node in the first storage system fails, it is determined whether the outstanding write corresponds to a host write to the backup node of the first storage system. If so, a retransmission message is sent to the second storage system. Otherwise, the data region associated with the outstanding write request is read from the first storage system, and a resynchronization message is sent to the second storage system.

Abstract: A multi-node data storage system comprises a first data storage system having an owner node and a backup node in a first location coupled to a second data storage system having an owner node and a backup node in a second location. Each storage system includes a copy of the same data volume. A failure of a node of the multi-node storage system is detected. An outstanding write request to the first storage system is identified. If the owner node in the first storage system fails, it is determined whether the outstanding write corresponds to a host write to the backup node of the first storage system. If so, a retransmission message is sent to the second storage system. Otherwise, the data region associated with the outstanding write request is read from the first storage system, and a resynchronization message is sent to the second storage system.