VxVM tasks represent long-term operations in progress on the system. Every task gives information on the time the operation started, the size and progress of the operation, and the state and rate of progress of the operation. You can change the state of a task, giving coarse-grained control over the progress of the operation. For those operations that support it, you can change the rate of progress of the task, giving more fine-grained control over the task.
New tasks take time to be set up, and so may not be immediately available for use after a command is invoked. Any script that operates on tasks may need to poll for the existence of a new task.
See the vxtask(1M) manual page.