摘要:
Described is a distributed copying technique that may be used in migrating large amounts of data from one or more source devices to one or more destination devices. The data source is divided into partitions. As Fibre Channel adapters (FAs) become available, each of the FAs may copy a partition of the data. In connection with specifying paths used for the distributed copying technique, a preferred path selection (source port-target port mapping) may be made by executing code in a controlling data storage system to perform discovery processing. The preferred path selection is used for the duration of the distributed copying unless the preferred path is unable to transmit data. A target port of the preferred path may be randomly selected from all accessible target ports, and/or in accordance with a specified portion of the target ports. Preferred paths may also be specified using an API (application programming interface).
摘要:
Described are techniques for use with online data copying or migration. Data is pushed from a source to a target device while one or both of the source and target devices are available for use by one or more host systems. The host systems may perform I/O operations to the source and/or target devices while the data migration is ongoing if a copy session is defined on the data storage system(s) of the source and/or target devices. A copying operation performs data migration from the source to the target device. A migration vector is used to indicate which portions of the source have been migrated. A change vector may be associated with each of the source and/or target devices to indicate portions that have been modified in order to perform a differential copy operation.
摘要:
Described are techniques for use with an error handling policy for a data storage system. Error handling criteria may be specified for controlling behavior of the data storage system upon the occurrence of an internal processing error occurring when performing an ancillary task associated with a data operation received by the data storage system. The error handling criteria may include a threshold counter value, and one or more of: a device, a specific device location or address, and a host. An error may be conditionally returned to the host upon the occurrence of an internal processing error in accordance with the error handling criteria.
摘要:
Described is a distributed copying technique that may be used in migrating large amounts of data from one or more source devices to one or more destination devices. The data source is divided into partitions. As Fibre Channel adapters (FAs) become available, each of the FAs may copy a partition of the data. In connection with specifying paths used for the distributed copying technique, a preferred path selection (source port-target port mapping) may be made by executing code in a controlling data storage system to perform discovery processing. The preferred path selection is used for the duration of the distributed copying unless the preferred path is unable to transmit data. A target port of the preferred path may be randomly selected from all accessible target ports, and/or in accordance with a specified portion of the target ports. Preferred paths may also be specified using an API (application programming interface).
摘要:
Described is a distributed copying technique that may be used in migrating large amounts of data from one or more source devices to one or more destination devices. The data source is divided into partitions. As Fibre Channel adapters (FAs) become available, each of the FAs may copy a partition of the data. A copy indicator value indicates the last partition delegated to an FA for copying. The last FA to complete copying is responsible for ensuring completed copying of any other data partitions delegated to an FA which has died during migration of the other data partitions. In the event that the last FA dies prior to completing its processing, additional steps are performed by other remaining FAs to copy all data partitions not known to be successfully migrated.
摘要:
A technique migrates data from a source array to a target array while preserving SCSI reservation compliance. The technique involves providing an active-to-passive instruction to the source array while a first SCSI reservation enables hosts to access data on the source array using MPIO software. The active-to-passive instruction directs the source array to transition devices from active mode to passive mode and, upon receipt of a next SCSI instruction, output an indicator indicating that the first SCSI reservation has been cleared. The technique further involves transitioning devices of the target array from passive mode to active mode and beginning a data transfer operation which transfers data from the source array to the target array. The technique further involves automatically effectuating formation of a second SCSI reservation in place of the first SCSI reservation, the second SCSI reservation providing host access to the data on the target array using MPIO software.
摘要:
A method for storing data includes writing the data to a temporary storage location and buffering a mirror request to copy the data from the temporary storage location to a mirror. Once all the data is present, the validity of the data is determined. If the data is valid, the mirror request is executed. Otherwise, the mirror request is deleted.
摘要:
Described is a technique for initialization of a device in a data storage system. A status indicating completion of the initialization is returned after setting initialization indicators associated with tracks of the device. The indicators indicate that the tracks of the device are to be initialized. As subsequent I/O operations for the device are processed, the tracks associated with the subsequent I/O operations are initialized prior to performing the I/O operation if the initialization indicators associated with the tracks are set. A background initialization task scans the initialization indicators and initializes tracks in accordance with the initialization indicators. Once a track has been initialized, its associated initialization indicator is cleared.
摘要:
In one aspect, a method includes providing a first storage volume to receive I/Os from a host and having a device ID, providing a second storage volume to receive the I/Os and having a device ID and performing a recovery that includes rebooting the host and recognizing, at the host, the second storage volume as the first storage volume using the device ID of the second storage volume being identical to the device ID of the first storage volume. The first storage volume is in an active mode and the second storage volume is in a passive mode.
摘要:
Described are techniques for processing data requests in connection with an I/O operation. A write data request is sent from a host to a target data storage system. The host performs a data validation, such as a checksum calculation, using the data of the data request. The data request is sent to the target data storage system. The target data storage system may be enabled to perform data validation processing on a per device basis by setting one or more device flag bits for a device. The target data storage system performs data validation processing in accordance with the flag bit settings of a device associated with a data request. A target checksum value using the data received on the target data storage system is determined and compared to the host checksum value in order to determined data validity. Data recovery processing is performed if data corruption is determined. A partial write of the data requested may be performed for those data portions occurring prior to the corrupted data that have been successfully validated.