Abstract: A method and apparatus for identifying process use on storage array resources is provided. A first process (e.g. an IO driver such as an MPIO driver) on each host collects process information of application processes running on that host. The process/device information is forwarded to the storage array where it is added to a process correlation data structure and correlated with assigned devices of the storage array. The host name that provided the process information is also added to the process correlation data structure. A name of the application is also correlated to the process name in the process correlation data structure. The date the device was last used is periodically updated in the process correlation data structure. The process correlation data structure may then be used to identify devices that have not recently been used and to identify the host, application, and process that uses the devices.

Abstract: In one aspect, a method includes receiving, at a storage array, a command to a virtual volume from a host, extracting a virtual volume index from the command; reading a table using the virtual volume index to determine the logical unit where the virtual volume is stored and executing the command at the logical unit with the virtual volume. The command is one of a read command to read data from the virtual volume or a write command to write data to the virtual volume.

Abstract: A computer-implemented method is disclosed to enhance command burst tolerance in a SCSI system. The method starts with receiving an initiator timeout value at a SCSI target, where the SCSI target is communicatively coupled with a SCSI initiator through a set of communication links, and where the initiator timeout value is associated with a timeout duration after which the SCSI initiator times out if receiving no response from the SCSI target after sending a SCSI command. After receiving the initiator timeout value, the SCSI target determines how long a SCSI command has been pending to be processed at the SCSI target. The SCSI target then returns a response for the SCSI command to the SCSI initiator within the timeout duration associated with the initiator timeout value even if the SCSI command is pending to be processed at the SCSI target.

Abstract: Masking information may be automatically determined for a host after zoning between the host and data storage system is complete. Processing may include the host sending host registration commands from host initiators. From registration information provided with the host registration commands, an initiator group may be determined for the masking view as including the initiators identified as belonging to the host. A port group may be determined as those target ports at which the host registration commands are received. A default storage group with a default device may be created. A masking view for the host may be created that includes the initiator group, the target port group and the default storage group whereby the masking view indicates that the first device is accessible or exposed, through each target port of the target port group, to each initiator of the initiator group.

Abstract: A data storage system provides asymmetric multi-path access to a storage device from a host computer using a storage protocol such as SCSI. Device state information is maintained indicating that one path of set of paths between the host computer and the storage device is a non-fully-functional path. In response to receiving device discovery commands from the host computer on the one path and the one path being indicated to be a non-fully-functional path, the data storage system returns respective good responses indicating that the storage device is accessible to the host computer via the non-fully-functional path. However, in response to receiving a test unit readiness command from the host computer on the one path and the one path being indicated to be a non-fully-functional path, an error response is returned which causes the host computer to select an alternative path of the set of paths for the data transfer.

Abstract: A computer-implemented method is disclosed to enhance link anomaly tolerance in a small computer system interface (SCSI) system. The method starts with detecting a SCSI command failed at a SCSI target, where the SCSI target is communicatively coupled with a SCSI initiator through a set of communication links and the failed SCSI command is sent from the SCSI initiator. After detecting the failure, the SCSI target withholds returning a response for the failure. Then the SCSI target checks a status of the set of communication links periodically within the withholding duration while the response for the failed SCSI command is withheld. The SCSI target returns the response for the failed SCSI command upon at least one of two conditions is met: (1) The withhold duration expires; (2) The set of communication links is determined to function normally based on checking the status of the set of communication links.

Abstract: In one aspect, a method includes receiving, at a storage array, a command to a virtual volume from a host, extracting a virtual volume index from the command; reading a table using the virtual volume index to determine the logical unit where the virtual volume is stored and executing the command at the logical unit with the virtual volume. The command is one of a read command to read data from the virtual volume or a write command to write data to the virtual volume.

Abstract: Determining whether to migrate from a source storage device to a target storage device includes determining if the target storage device is accessible by hosts that access the source storage device, determining if reservation information stored on the target storage device matches reservation information stored on the source storage device and migrating from the source storage device to the target storage device if the target storage device is accessible by hosts that access the source storage device and reservation information stored on the target storage device matches reservation information stored on the source storage device. Determining whether to migrate from a source storage device to a target storage device may also include, in response to initially determining that the reservation information stored on the target storage device does not match the reservation information stored on the source storage device, attempting to match the reservation information.

Abstract: Migrating data from a source storage device to a target storage device includes creating new paths to the target storage device, setting the target storage device to a state where I/O operations are initially accepted, where accepted I/O operations are rejected some time after acceptance, setting the source storage device to a state where at least some I/O operations are rejected, transferring metadata corresponding to the source storage device to the target storage device, where state information is transferred from the source storage device to the target storage device and setting the target storage device to a state where I/O operations are accepted and performed. Migrating data from a source storage device to a target storage device may also include creating new volumes on the target storage device and transferring data from the source storage device to the target storage device.

Abstract: Various embodiments of a method and system for inhibiting reads to non-guaranteed data in remapped portions of a storage medium are disclosed. In one embodiment, a method of managing a non-read list associated with a storage medium involves: detecting a bad portion of the storage medium, remapping the bad portion's address to a new portion of the storage medium, copying the data stored to the bad portion to the new portion and, if the copy is unsuccessful, adding the address of the new portion to the non-read list, and inhibiting a read to the new portion if the new portion's address is listed on the non-read list. The address of the new portion may be removed from the non-read list in response to a successful write to the new portion.

Abstract: Various embodiments of a method and system for inhibiting reads to non-guaranteed data in remapped portions of a storage medium are disclosed. In one embodiment, a method of managing a non-read list associated with a storage medium involves: detecting a bad portion of the storage medium, remapping the bad portion's address to a new portion of the storage medium, copying the data stored to the bad portion to the new portion and, if the copy is unsuccessful, adding the address of the new portion to the non-read list, and inhibiting a read to the new portion if the new portion's address is listed on the non-read list. The address of the new portion may be removed from the non-read list in response to a successful write to the new portion.