Abstract: Described are techniques for indicating a state associated with a device. A request is received over a path for information about a device. A response to the request is sent. The response indicates a state regarding the device on the path. The response has a response status of good and a payload of a varying size. The payload is truncated at a location prior to that at which a device identifier for the device is expected. In accordance with the response, a state regarding the device on the path is determined.

Abstract: Technology for minimizing disruptions when host data on a physical volume is encapsulated into a virtualization layer or de-encapsulated is disclosed. Evaluation of a physical volume used as data storage for a virtualization layer before committing to direct access to the physical volume is enabled by preventing direct access before presenting the physical volume directly to the host and by preventing the virtualization layer from moving data on the physical volume while redirecting to the physical volume a first plurality of I/O requests that were directed to the virtualization layer.

Abstract: The invention provides a system to reclaim space identified as no longer in use and comprises a vLUN, a thinly provisioned mapped LUN, a mapping layer, and a data reduction engine. Chunks of data are stored at logical chunk addresses (LCAs) in the vLUN and are mapped to corresponding physical chunk addresses (PCAs) in the thinly provisioned mapped LUN. The data reduction engine performs a data reduction process on a first logical chunk of data stored at a first LCA in the vLUN, where the first logical chunk has a size that is a nonzero integer multiple of the size of the storage extent of the thinly provisioned mapped LUN. After the data reduction process, the PCA associated with the first logical chunk is no longer needed, and the thinly provisioned mapped LUN is instructed to deallocate the PCA associated with the first logical chunk that is no longer needed.

Abstract: Described are techniques for indicating a state associated with a device. A request is received over a path for information about a device. A response to the request is sent. The response indicates a state regarding the device on the path. The response has a response status of good and a payload of a varying size. The payload is truncated at a location prior to that at which a device identifier for the device is expected. In accordance with the response, a state regarding the device on the path is determined.

Abstract: Described are techniques for indicating a state associated with a device. A request is received over a path for information about a device. A response to the request is sent. The response indicates a state regarding the device on the path. The response has a response status of good and a payload of a varying size. The payload is truncated at a location prior to that at which a device identifier for the device is expected. In accordance with the response, a state regarding the device on the path is determined.

Abstract: Systems and methods are provided for selecting a path for an I/O in a storage area network. In one embodiment, a method comprises receiving path configuration information for paths associated with a host device connected to the storage area network, a listing of components within the storage area network, and a notification of a component failure within the storage area network. The method may also comprise correlating the received path configuration information, the received listing of components, and the received notification of component failure to determine one determine one or more paths associated with the host device affected by the component failure. The method may further comprise transmitting to the host device an alert for the one or more affected paths.

Abstract: A method is provided for providing an operating system (OS) independent input/output (I/O) filter driver capable of encrypting at least a portion of a logical unit (LUN), the method comprising the unordered steps of: providing an I/O filter driver component to an I/O stack for a host in communication with the LUN; determining, based at least in part on at least one of OS requirements and an arrangement of data on the LUN, at least one region in the LUN that contains data that is used below the I/O filter driver in an I/O stack on the host; and performing at least one of a read and a write of the one or more regions while keeping the one or more regions in plaintext, while permitting other regions of the LUN to be at least one of encrypted and decrypted.

Abstract: Systems and methods are provided for selecting a path for an I/O in a storage area network. In one embodiment, a method comprises receiving path configuration information for paths associated with a host device connected to the storage area network, a listing of components within the storage area network, and a notification of a component failure within the storage area network. The method may also comprise correlating the received path configuration information, the received listing of components, and the received notification of component failure to determine one or more paths associated with the host device affected by the component failure. The method may further comprise transmitting to the host device an alert for the one or more affected paths.

Abstract: An in-band protocol transport carries command-response protocol communications between first and second functional components of a storage input/output (I/O) interface stack, for example to control encryption-related processing of storage I/O commands. A storage read command used as a protocol transport message has protocol data in a read data buffer, and predetermined read address information, such as a prime-numbered starting block address and a small, odd-valued length value, unlikely to occur in normal (non-transport) storage read commands. The second functional component determines that the storage read command contains the predetermined read address information, indicating that the storage read command is a protocol transport message rather than a normal read. For greater confidence, it also determines that the protocol data in the read data buffer includes protocol identification data such as a protocol signature.

Abstract: A method is provided for controlling I/O request access to an encrypted storage device when the encryption key for the encrypted storage device is not available.

Abstract: The invention provides a system to reclaim space identified as no longer in use and comprises a vLUN, a thinly provisioned mapped LUN, a mapping layer, and a data reduction engine. Chunks of data are stored at logical chunk addresses (LCAs) in the vLUN and are mapped to corresponding physical chunk addresses (PCAs) in the thinly provisioned mapped LUN. The data reduction engine performs a data reduction process on a first logical chunk of data stored at a first LCA in the vLUN, where the first logical chunk has a size that is a nonzero integer multiple of the size of the storage extent of the thinly provisioned mapped LUN. After the data reduction process, the PCA associated with the first logical chunk is no longer needed, and the thinly provisioned mapped LUN is instructed to deallocate the PCA associated with the first logical chunk that is no longer needed.

Abstract: A system configured to optimize access to stored chunks of data is provided. The system comprises a vLUN layer, a mapped LUN layer, and a mapping layer disposed between the vLUN and the mapped LUN. The vLUN provides a plurality of logical chunk addresses (LCAs) and the mapped LUN provides a plurality of physical chunk addresses (PCAs), where each LCA or PCA stores a respective chunk of data. The mapping layer defines a layout of the mapped LUN that facilitates efficient read and write access to the mapped LUN.

Abstract: Systems and methods are provided for disabling an array port in an enterprise storage system. In one embodiment, a system comprises a storage area network (SAN), a plurality of hosts, an array controller comprising a plurality of array ports, and a management server. The management server receives a request to disable an identified one of the plurality of array ports and identifies, from a configuration table stored in the management system server, one or more of the plurality of hosts having at least one path to the identified array port. The management server transmits an instruction to the one or more of the plurality of hosts to disable paths to the identified array port.

Abstract: Systems and methods are provided for disabling a device in an enterprise storage system. In one embodiment, a method comprises receiving information identifying a device in a storage area network that is scheduled for an outage. The method further determines one or more paths impacted by the outage of the device, generates a notification identifying the determined one or more paths, and transmits the notification to one or more hosts having paths to the device.

Abstract: Methods and systems are disclosed that enable data migration from a source logical volume to a target logical volume in signal communication with the source logical volume with minimal disruption to the accessibility of that data. The coherency of data on the source logical volume and the target logical volume is confirmed. A first pseudoname is unmapped from a source logical volume identifier, and a second pseudoname is unmapped from a target logical volume identifier. A logical volume identifier includes information specific to the logical volume it identifies. The first pseudoname is then mapped to the target logical volume identifier.

Abstract: Methods and apparatus for non-disruptive upgrade by redirecting I/O operations. With this arrangement, a driver upgrade does not require restarting an application. In one embodiment, a method includes installing on a computer a legacy upgrade module in a kernel having a legacy driver with first and second loadable extensions for handling input/output operations for applications to and from devices, retrieving and storing static configuration data from the legacy driver, transferring the stored static configuration data to a new driver, obtaining runtime device configuration data from the devices and transferring the runtime device configuration data to the new driver, and filtering device input/output operations such that prior to cutover input/output operations are directed by the LUM through device stacks for the legacy driver and after cutover input/output operations are directed to the new driver.

Abstract: Methods and systems are provided for minimizing disruptions when host data on a source logical unit is migrated onto a target logical unit. I/O requests are managed in a particular order during various states of the migration. After the target logical unit is synchronized with the source logical unit and before a commitment to the target logical unit is made, the target logical unit can be evaluated. At that point, the migration can be aborted. During the evaluation of the target logical unit, I/O requests that were directed to the source logical unit are redirected to the target logical unit and I/O requests that were directed to the target logical unit are redirected to the source logical unit. The disclosed methods and systems are equally effective at enabling less disruptive virtualization of a source logical unit as a target logical unit.

Abstract: Described are techniques for overriding an existing device reservation. Discovery processing is performed by a first data storage system to locate a specified device. The discovery processing includes determining whether there is a reservation conflict for said device of a second data storage system. If there is a reservation conflict for the device, a command is issued from the first data storage system to the second data storage system during said discovery processing to create an override for said reservation conflict. The override causes processing to be performed at a subsequent point in time so that an existing reservation associated with the reservation conflict is overridden in connection with performing a first process on said first data storage system.

Abstract: Methods and systems for preserving a disk geometry when relabeling a storage device containing data migrated from a previous data storage device having different disk geometry. Prior to relabeling, the label of the storage device includes information on the disk geometry of the previous data storage device. An exemplary method includes reading the label of the storage device in response to a request for information related to a disk geometry of the storage device, which is normally answered without reference to the label of the storage device, and reporting the information related to the disk geometry from the label if the label is associated with an operating system that considers a geometry of a storage device when partitioning.

Abstract: Methods and systems for preserving disk geometry when relabeling a data volume encapsulated in a virtual storage device that presents a different disk geometry than the data volume. An exemplary method includes maintaining information from a label of the data volume in a memory associated with the virtual storage device and intercepting a request for information related to a disk geometry of the encapsulated data volume that is normally answered without reference to the label. The request may be associated with a command to relabel the encapsulated data volume. The method also includes reporting the information from the label of the data volume related to the disk geometry of the data volume if the label is associated with an operating system that considers a geometry of a data volume when partitioning.