VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

Monitoring and Controlling Tasks
188 VERITAS Volume Manager Administrator’s Guide
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. The administrator can change the state of a
task, giving coarse-grained control over the progress of the operation. For those
operations that support it, the rate of progress of the task can be changed, giving more
fine-grained control over the task.
vxtask Operations
The vxtask command supports the following operations:
abort Causes the specified task to cease operation. In most cases, the operations
“back out” as if anI/O erroroccurred, reversing what has been done so far to
the largest extent possible.
list Liststasks runningon the systeminone-line summaries. The -l optionprints
tasks in long format. The -h option prints tasks hierarchically, with child
tasks following the parent tasks. By default, all tasks running on the system
are printed. If a taskid argument is supplied, the output is limited to those
taskswhose taskid or task tagmatchtaskid.The remainingargumentsare
used to filter tasks and limit the tasks actually listed.
monitor Prints information continuously about a task or group of tasks as task
information changes. This allows you to track the progression of tasks.
Specifying -l causes a long listing to be printed. By default, short one-line
listings are printed. In addition to printing task information when a task state
changes, outputis also generated when the taskcompletes. When this occurs,
the state of the task is printed as EXITED.
pause Puts a running task in the paused state, causing it to suspend operation.
resume Causes a paused task to continue operation.
set Changes modifiable parameters of a task. Currently, there is only one
modifiable parameter, slow[=iodelay], which can be used to reduce the
impact that copy operations have on system performance. If slow is
specified, this introduces a delay between such operations with a default
value for iodelay of 250 milliseconds. The larger the value of iodelay that is
specified, the slower is the progress of the task and the fewer system
resources that it consumes in a given time. (The slow attribute is also
accepted by the vxplex, vxvol and vxrecover commands.)