Abstract: A storage device controller coupled to a storage device having a multiple locations for storing data coupled to may receive a WRITE ANYWHERE command including write data but not specifying a location of the storage device where the write data should be stored. The controller responds to the WRITE ANYWHERE command by selecting one or more unused locations of the storage device, and writing the write data in the one or more unused locations of the storage device. After writing the write data to the storage device, the controller may report where the write data is stored to the host. The host may also issue FREE commands to the controller specifying locations of the storage device which should be identified as unused. In response to a received FREE command, the controller may store information in a memory indicating that the location specified by the FREE command is unused.

Abstract: A storage array interconnection fabric may be configured using multiple independent paths. A storage system including a plurality of communication paths is configured for connecting each node of a plurality of nodes forming an interconnection fabric. Each of the communications paths is an independent communications path. In addition, a first portion of the plurality of nodes is configured to communicate with a plurality of mass storage devices such as disk drives. A second portion of the plurality of nodes may be configured to communicate with a host.

Abstract: A protection domain for a set of errors is defined using an association between data and first integrity metadata to protect data traversing an input/output datapath. The datapath has a storage device as one endpoint and a first generation integrity point for a host as an opposite endpoint. A first sub-domain is defined within the protection domain using an association between the data and second integrity metadata to further protect a portion of the datapath having a second generation integrity point as one endpoint. In another aspect, a second sub-domain is defined within the protection domain using an association between the data and third integrity metadata further protect data traversing a portion of the datapath having a third generation integrity point as one endpoint. The first and second sub-domains are nested within the protection boundary and may be in a hierarchical relationship.

Abstract: In one embodiment, a storage subsystem includes a plurality of storage arrays each including a plurality of storage devices. The storage subsystem also includes a plurality of array controllers each coupled to one or more of the plurality of storage arrays. One or more of the arrays corresponds to a failure group. Each array controller may create a storage volume including storage devices belonging to one or more of plurality of storage arrays. In addition, the storage subsystem includes a redundancy controller that may be configured to implement N+K redundancy. The redundancy controller includes configuration functionality that may determine a number of redundant system data blocks to be stored on different storage devices for a given stripe of data that is dependent upon particular values of N and K and upon physical system configuration information.

Abstract: Diagnosis of corruption in interrelated data entities uses a graph of nodes and edges. Datum nodes represent the data entities, relationship nodes represent the relationships among the data entities. The datum nodes are connected through their relationship nodes by the edges. When corruption is detected, the relationships are analyzed and each edge connecting a datum node to a relationship node is removed from the graph when the corresponding relationship is invalid. The datum nodes that remain connected to their relationship nodes form a subgraph and the corresponding data entities are considered correct. In one aspect, if more than one subgraph is formed, the datum nodes in the largest are used. In another aspect, the data entities and relationships are analyzed to create the graph when the data entities are assumed correct. The data entities may be data and metadata of various types that can be associated with the data.

Abstract: A method for detecting errors in streaming media devices is described. In one embodiment, when a command to write a block of data to a streaming media device is received, integrity metadata associated with the data block is attached to the data block and written to the streaming media device together with the data block. Subsequently, when a read command pertaining to this data block is received, new integrity metadata is determined and compared to the attached metadata. If the new integrity metadata does not match the attached metadata, an error message is generated.

Abstract: A storage system comprises a storage array controller and a storage array, which includes multiple storage devices and disk drive controllers. The storage array controller issues scrubbing operation commands to one or more of the disk drive controllers. In response, each disk drive controller that receives a scrubbing operation command reads data from within a data range from at least one of the disk drives, calculates a new checksum for the data, and compares the new checksum to a preexisting checksum for the data. If the new checksum doesn't equal the preexisting checksum, the data within the data range is determined to be erroneous.

Abstract: A method for detecting a phantom write error in a data storage system is described. In one embodiment, upon receiving a read command pertaining to a data block stored on a storage medium, two version identifiers associated with the data block are compared. A first version identifier is stored within the data block and a second version identifier is stored outside of the data block. If the version identifiers do not match, the possible occurrence of a phantom write error is detected.

Abstract: A storage system comprises a storage array controller and a storage array, which includes multiple disk drives and disk drive controllers. The storage array controller issues scrubbing operation commands to one or more of the disk drive controllers. In response, each disk drive controller that receives a scrubbing operation command reads data from within a data range from at least one of the disk drives, calculates a new checksum for the data, and compares the new checksum to a preexisting checksum for the data. If the new checksum doesn't equal the preexisting checksum, the data within the data range is determined to be erroneous.

Abstract: Various embodiments of systems and methods for implementing a streaming I/O protocol are disclosed. In some embodiments, a method may involve: receiving a packet initiating a streaming write operation, where the packet indicates that the size of the streaming write is larger than the size of the packet; initiating a write access having a size larger than the size of the packet to a storage device; receiving subsequent packets included in the streaming write operation; and writing data received in the subsequent packets to the storage device as part of the write access initiated in response to the earlier packet. In some embodiments, streaming read operations may also be supported.

Abstract: A single field replaceable storage or computer system may include a processor coupled to a peripheral bus by a bridge device. The field replaceable unit (FRU) may also include system memory coupled to the processor and a network interface coupled to the peripheral bus. One or more drive controllers may also be included coupled to the peripheral bus. Additionally, the single field replaceable unit includes an array of disk drives coupled to the one or more drive controllers. The array of disk drives may be configured as one or more RAID logical volumes and exported or presented to client machines as one or more file systems through the network interface. The processor, system memory, network interface, drive controllers, and array of disk drives are all packaged together as a single field replaceable unit. The processor, system memory, network interface, drive controllers, and array of disk drives may be configured not to be individually field serviceable or replaceable.

Abstract: Data integrity errors in a redundant storage array are handled by storing a plurality of data blocks having a horizontal redundant relationship and storing a plurality of checksums, each checksum having a vertical redundant relationship with a corresponding one of the plurality of data blocks. In response to detection of a data integrity error in at least one of the plurality of data blocks, the vertical redundant relationships between each of the checksums in the plurality of checksums and the corresponding data blocks are reviewed and the horizontal redundant relationship between the data block having the data integrity error and the remaining data blocks in the plurality of data blocks is also reviewed. The results of these reviews of the redundant relationships can be used to diagnose and repair the data integrity error.

Abstract: A method embodied as software or firmware code permits the adaptation of disk drives employing write-back caching to reduce the possibility of lost data from the write cache. In one embodiment, the method is integrated with the host operating system software employed by a host computer coupled to the disk drive. The method issues write requests to the disk drive as it receives them from the applications running on the host computer. The disk drive processes the issued requests as it is designed to, using write-back caching techniques. After each request is cached, the disk drive controller acknowledges the write request back to the host. The host delays communicating the acknowledgements back to their originating applications until the data has been actually written to the disk media. Because write-back caching does not commit cached requests to disk on a regular basis, the host software simply forces the disk drive to execute cached write requests on a regular basis using a CACHE_FLUSH command.

Abstract: A storage device is monitored for data integrity errors and each detected data integrity error is stored in a count. When that count reaches a threshold limit, the storage device is placed into a forced failure state.

Abstract: A method for embedding integrity metadata. In one exemplary embodiment, a plurality of integrity metadata segments is determined. Each integrity metadata segment is associated with a segment of user data. The user data is mapped to a plurality of physical sectors, each physical sector containing a segment of user data and the associated integrity metadata segment. For one exemplary embodiment, a common I/O data block size is determined, and its data is mapped into a number of 512-byte sectors. The number of 512-byte sectors corresponds to the number required for the common I/O data block size plus one or more additional 512-byte sectors. This creates additional space in each sector to accommodate the integrity metadata. Integrity metadata for each data segment of the common I/O size is determined. The integrity metadata for each sector is mapped to the additional space of each sector.

Abstract: A switch is presented including a host input/output (I/O) port adapted for coupling to a controller, multiple device I/O ports each adapted for coupling to at least one device, and logic coupled between the host I/O port and the device I/O ports configured to selectively form a communication channel between the host I/O port and one of the device I/O ports. The switch may operate in a connected mode and a disconnected mode. When in the switch is in the disconnected mode, the logic may not form a communication channel between the host I/O port and any of the device I/O ports. In an ATA embodiment, the switch may comply with an AT attachment (ATA) standard, and thus be an ATA switch. The host I/O port may be adapted for coupling to an ATA controller, the device I/O ports may be adapted for coupling to at least one ATA device, and the logic may selectively form an ATA communication channel between the host I/O port and one of the device I/O ports.

Abstract: Various embodiments of systems and methods for implementing a streaming I/O protocol are disclosed. In some embodiments, a method may involve: receiving a packet initiating a streaming write operation, where the packet indicates that the size of the streaming write is larger than the size of the packet; initiating a write access having a size larger than the size of the packet to a storage device; receiving subsequent packets included in the streaming write operation; and writing data received in the subsequent packets to the storage device as part of the write access initiated in response to the earlier packet. In some embodiments, streaming read operations may also be supported.

Abstract: A system may include mirroring logic, a controller, and first and second devices (e.g., data storage devices). The first and second devices may include multiple registers. The mirroring logic may be configured in a first mode wherein the mirroring logic allows the registers of the first device to be accessed from the controller and prevents the registers of the second device from being accessed from the controller. The mirroring logic may be configured in a second mode wherein the mirroring logic allows the registers of the second device to be accessed from the controller and prevents the registers of the first device from being accessed. The first and second devices may be configured via the mirroring logic such that the first and second devices are selected simultaneously. When selected simultaneously, the first and second devices may carry out a subsequently issued command substantially simultaneously.

Abstract: A storage device controller configured for coupling to a storage device (e.g., a hard disk drive) having a multiple locations for storing data. The controller is coupled to receive a WRITE ANYWHERE command including write data. Unlike a conventional write command, the WRITE ANYWHERE command does not specify a location of the storage device where the write data is to be stored. The controller responds to the WRITE ANYWHERE command by: (i) selecting one or more unused locations of the storage device, and (ii) writing the write data to the storage device, wherein the writing of the write data includes directing the storage device to store the write data in the one or more unused locations of the storage device. At least a portion of the write data in stored in each of the one or more unused locations. The controller may be coupled to receive the WRITE ANYWHERE command from a host configured to track usage of the locations of the storage device.

Abstract: An embodiment of the present invention provides a method for validating data using version identifier IMD along with at least one other type of IMD embedded within a data block. Each type of IMD corresponds to a data verification operation. In conjunction, the multiple data verification operations protect against a larger class of data corruption errors than each would individually. For one embodiment, a data block is accessed, the data block being one of a plurality of data blocks mapped to a physical sector. Each of the data blocks contains a user data segment and an associated IMD segment. Each of the IMD segments includes a version identifier IMD and at least one other type of IMD. The data block is validated by verifying the version identifier IMD and at least one of the at least one other type of IMD.