摘要:
Data validation systems and methods are provided. Data is recorded in N data chunks on one or more storage mediums. A first validation chunk independently associated with said N data chunks comprises first validation information for verifying accuracy of data recorded in said N data chunks. The first validation chunk is associated with a first validation appendix comprising second validation information, wherein the first validation appendix is stored on a first storage medium independent of said one or more storage mediums.
摘要:
Embodiments of the invention relate to correcting erasures in a storage array. A read stripe is received from a plurality of n storage devices. The read stripe includes an array of entries arranged in m rows and n columns with each column corresponding to one of the storage devices. The entries include data entries and mr+s parity entries. Each row contains at least r parity entries generated from the data entries according to a partial maximum distance separable (PMDS) code. It is determined that the read stripe includes at least one erased entry, at most mr+s erased entries and that no row has more than r+s erased entries. The erased entries are reconstructed from the non-erased entries, resulting in a recovered read stripe.
摘要:
Data storage reliability is maintained in a write-back distributed data storage system including multiple nodes. Information is stored as a stripe including a collection of a data strips and associated parity strips, the stripe distributed across data and parity nodes. Each data node maintains the data strip holding a first copy of data, and each parity node maintains a parity strip holding a parity for the collection of data strips. A driver node initiates a full-stripe-write parity update protocol for maintaining parity coherency in conjunction with other nodes, to keep the relevant parity strips coherent. Parity is determined directly by computing parity strips for all data strips of a stripe. Any node may function as a driver node.
摘要:
Embodiments of the invention enable a storage cache, comprising flash memory devices, to have direct block access to the flash such that the physical block addresses are presented to the storage system's cache layer, which thereby controls the storage cache data stream. An aspect of the invention includes a caching storage system. The caching storage system comprises a plurality of flash memory units organized in an array configuration. Each of the plurality of flash memory units includes at least one flash memory device and a flash unit controller. Each flash unit controller provides the caching storage system with direct physical block access to its corresponding at least one flash memory device. The caching storage system further comprises a storage cache controller. The storage cache controller selects physical block address locations (within a flash memory device) to be erased where data are to be written, issues erase commands to a flash unit controller corresponding to the selected physical block address locations, and issues page write operations to a set of erase blocks.
摘要:
Rebuilding lost data in a distributed redundancy data storage system including multiple nodes, is provided. User data is stored as a collection of stripes, each stripe comprising a collection of data strips and associated parity strips, the stripes distributed across multiple corresponding data owner nodes and multiple corresponding parity owner nodes. A data owner node maintains the associated data strip holding a first copy of data, and a parity owner node maintains a parity strip holding a parity for the collection of data strips. Upon detecting a failure condition, the owner node initiates a rebuilding protocol for recovery of lost data and/or parity it owns. The protocol includes reconstruction of lost data or parity by a computation involving data and/or parity from a recovery strip set in a stripe, wherein a recovery strip set contains at least one surviving data or parity strip. The recovery strip set for a lost data strip contains at least one surviving parity strip.
摘要:
A computer implemented method, apparatus, and computer usable program product for managing redundant array of independent drives. In response to a failure of a hard disk in a first RAID array, the process calculates an amount of free capacity available across a set of remaining hard disks in the first RAID array. The set of remaining hard disks comprises every hard disk associated with the first RAID array except the failed disk. In response to a determination that the amount of free capacity is sufficient to re-create the first RAID array at a same RAID level, the process reconstructs the first RAID array using an amount of space in the set of remaining drives utilized by the first RAID array and the free capacity to form a new RAID array without utilizing a spare hard disk.
摘要:
Data validation systems and methods are provided. Data is recorded in N data chunks on one or more storage mediums. A first validation chunk independently associated with said N data chunks comprises first validation information for verifying accuracy of data recorded in said N data chunks. The first validation chunk is associated with a first validation appendix comprising second validation information, wherein the first validation appendix is stored on a first storage medium independent of said one or more storage mediums.
摘要:
Methods are provided for detecting and correcting dropped writes in a storage system. Data and a checksum are written to a storage device, such as a RAID array. The state of the data is classified as being in a “new data, unconfirmed” state. The state of written data is periodically checked, such as with a timer. If the data is in the “new data, unconfirmed” state, it is checked for a dropped write. If a dropped write has occurred, the state of the data is changed to a “single dropped write confirmed” state and the dropped write error is preferably corrected. If no dropped write is detected, the state is changed to a “confirmed good” state. If the data was updated through a read-modified-write prior to being checked for a dropped write event, its state is changed to an “unquantifiable” state.
摘要:
A configuration management subsystem of a subsystem array system assigns heat producing devices to clusters such that the number of devices activated will not create overheating, regardless of which limited set of clusters is activated. The subsystem receives the dimensions of the disk array, the number of devices, the number of cluster groups and the maximum number of clusters that can be operated substantially simultaneously, and the dimensions of a critical box that defines an arrangement of the devices into cells such that, if a device is assigned to each cell of the critical box and all devices are operated simultaneously, then thermal operating restrictions of the devices will be exceeded. The system first executes simple numbering loop operations to determine, if they exist, dimensions of a building block subarray that meet certain requirements relative to the input parameters. Using this building block subarray, the system then executes other simple numbering loop operations in which number labels are assigned to the disk devices (representing assignment of devices to disjoint clusters) such that if the maximum number of clusters are operating simultaneously, in every critical box subarray at least one device will not be operated.
摘要:
Embodiments of the invention relate to storing data in a storage array. An aspect of the invention includes receiving and arranging read data in array that includes m rows and n columns of entries, with each entry including at least one sector. In the array, mr+s locations are assigned to parity entries, such that each row has at least r parity entries. The parity entries correspond to a partial-maximum distance separable (PMDS) code that allows recovery from up to r erasures in each of the m rows as well as s additional erasures in any locations in the data array, where s is an integer greater than zero. The write data and the associated parity entries are written to the set of storage devices.