Abstract: Tracks of data or other data units are copied from a primary storage system to a secondary storage system. For multiple-track or multiple-data unit transfers, a group of tracks or data units which are sequentially related are transferred. A respective task is defined at the primary storage system for monitoring a progress of the transfer of each of the respective data units in a group. A state is maintained for monitoring a progress of the transfer of the group responsive to the progress of each of the tasks. A normal state is selected when there are no failed tasks. A recovery state is selected when there is a failure, and the status of the remaining tasks is being ascertained. A retry state is selected following the recovery state to retry the failed tasks. A failed state indicates an unrecoverable failure.

Abstract: Tracks of data or other data units are copied from a primary storage system to a secondary storage system. For multiple-track or multiple-data unit transfers, a group of tracks or data units which are sequentially related are transferred. A respective task is defined at the primary storage system for monitoring a progress of the transfer of each of the respective data units in a group. A state is maintained for monitoring a progress of the transfer of the group responsive to the progress of each of the tasks. A normal state is selected when there are no failed tasks. A recovery state is selected when there is a failure, and the status of the remaining tasks is being ascertained. A retry state is selected following the recovery state to retry the failed tasks. A failed state indicates an unrecoverable failure.

Abstract: An apparatus, system, and method are provided for maintaining task prioritization and load balancing of I/O tasks on servers coupled by a plurality of communication channels. The apparatus includes a task controller for maintaining system resources on a failed target channel while resubmitting an unsuccessful task to a different channel. Also, the apparatus includes an upgrade module for upgrading a task prioritization level of a failed I/O task. Additionally, a load module is provided for balancing I/O tasks evenly across the plurality of communication channels according to a prioritization algorithm. The system includes the task controller and a device controller configured to interface with the task controller. The method includes a computer readable medium with computer readable code for selecting a channel, upgrading the prioritization level of a failed task, and maintaining resources on the failed channel while resubmitting the failed I/O task on a different channel.