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NAMEvxtask — list and administer Volume Manager tasks SYNOPSISvxtask abort taskid vxtask
[-ahlpqr ]
[-g dg_name
[-g dg_name...]]
[[-G dg_name]
-v volume
[-v volume...\]]
[-i taskid]
list [taskid...\] vxtask pause taskid vxtask resume taskid vxtask
[-i taskid]
set name=value taskid
[-c count]
[-t time]
[-w wait_interval]
[-ln ]
monitor [taskid[taskid...\]] DESCRIPTIONThe vxtask utility performs basic administrative operations on
Volume Manager tasks that are running on the system.
Operations include listing tasks (subject to filtering),
modifying the state of a task (aborting, pausing, resuming),
and modifying the rate of progress of a task. Volume Manager tasks represent long-term operations in progress on the
system. Every task provides the time the operation
started, the size and progress of the operation, and the operation's
state and rate of progress (throttle). You can change
the state of a task, giving coarse-grained control over an operation's
progress. For those operations that support throttling, you can
change the rate of progress of a task,
giving more fine-grained control over the task. The majority of tasks represent I/O being performed to objects.
Operations such as read-writeback recovery for mirrored volumes,
parity recalculation for RAID-5 volumes, volume relayouts,
and so forth, all involve moderate to large amounts of I/O.
Tasks that represent operations that perform I/O directly are referred to as
basic tasks. The task progress information for basic tasks
consists of the starting and ending block of the I/O to be performed
and the offset to which the I/O has currently completed. Some operations, such as vxrecover and starting RAID-5
volumes, may require multiple tasks to complete the
operation. vxrecover may determine that many recoveries are
required, some that must be performed serially. Starting a RAID-5
volume requires that its log (if any) be replayed and cleared, its
parity be recalculated (if necessary), any stale subdisks be
resynchronized (if needed), and that these tasks be performed
serially. In these and similar cases, an overall task is created to
keep track of the underlying basic tasks being performed, and these
are known as parent tasks. The progress information for parent
tasks are the total number of subtasks required to complete the
overall operation; the number of subtasks completed; and the number of
subtasks currently running. Every task is given a unique task identifier. This is a numeric
identifier for the task that can be specified to the vxtask
utility to specifically identify a single task. Tasks also contain the following information:
- task tag
A task's tag is a string that you can specify to make
administration easier. It is usually set by the command
that initiates the task. For most utilities,
the -t tasktag option allows a tag to be specified
as a sequence of up to 16 alphanumeric characters. - task type
The task's type describes the specific operation that is being
performed. For example, attaching a plex to a volume results in an
atomic copy loop, which is represented by an ATOMIC_COPY task. - description
Describes the utility operation on whose behalf the I/O is being
performed. For example, both a volume start and a plex attach can
result in an atomic copy loop and thus an ATOMIC_COPY task. The
description of the operation attempts to disambiguate between tasks
that are performing the same basic work. - object
Most tasks are related to a specific object, usually the volume within
which the operation is taking place. - parent
Some utilities require multiple operations to fulfill a request. For
example, the vxrecover utility may need to start many
different volumes. In these cases, the subtasks list their parent. - progress information
Each task has an indication of its starting point and ending point,
and an indication as to what point it has progressed so far. Combined
with the work time, this allows the amount of time remaining until
completion to be estimated for some tasks. - state
Each task has one of three states: RUNNING, PAUSED or
ABORTING. - time
Each task notes its starting time and the total amount of time spent
doing work.
KEYWORDS- abort|pause|resume
These three operations request that the specified task change its state.
pause puts a running task in the paused state,
suspending its operation. resume continues the operation
of a paused task.
abort stops the operation of the specified.
In most cases,
the operations "back out" in a manner
similar to when an I/O error occurs,
reversing as much as possible what's been done so far. - list
List tasks running on the system in one-line summaries.
By default, all tasks running on the system are printed.
If a taskid argument is supplied, the output is limited to those
tasks whose taskid or task tag match taskid. The remaining
options filter and limit the listed tasks as follows:
- -a
Limits the output to tasks in the aborting state. - -g dg_name
Limits the listed tasks to those tasks running on objects in the
diskgroup dg_name. - -G
Distinguishes between volumes with the same name
in different diskgroups; see
vxintro(1M). - -h
Prints tasks hierarchically
with a task's child tasks following the parent task. - -l
Prints tasks in long format. - -p
Limits the output to tasks in the paused state. - -q
Supresses printing of column headings. - -r
Limits the output to tasks in the running state. - -v volume
Limits the output to tasks whose object is volume.
Any task meeting any of the criteria specified are printed. That is,
if -v foovol and -p are specified,
then any task operating
on foovol or that is paused are printed. If -h were also
specified, then those tasks and all their children would be listed. - monitor
The monitor operation continuously prints information
about a task or group of tasks as the task information changes.
The -l option specifies printing a long listing.
The default is to print one-line listings. The monitor command
accepts the following options:
- -c count
Prints count sets of task information, then exits. - -n
Monitors not only the tasks specified on the command line,
but also any tasks newly registered while the program is
running. - -t time
Exits after time seconds. - -w interval
Prints the string "waiting..." when interval
seconds pass with no output activity.
In addition to printing task information when a task state changes,
output is also generated when the task completes. When this occurs,
the task state is printed as EXITED (see the OUTPUT section). - set
The set operation changes modifiable parameters of a task.
There is only one modifiable parameter for tasks: the
slow attribute, which represents a throttle on the task
progress.
The larger the slow value,
the slower the progress of the task and
the fewer system resources it consumes in a given time. (The
slow attribute is the same attribute that many commands,
such as vxplex, vxvol and vxrecover,
accept.)
OUTPUTThere are two output formats printed by vxtask: a short,
one-line summary format per task, and a long task listing. The short
listing attempts to provide the most used task information for quick
perusal, displaying the following fields from left to right:
- 1.
The task ID for the task. - 2.
The task ID of the task's parent, if any. If the task has no parent,
this field is left blank. - 3.
The task type and state, separated by a slash (/). The type field is
a description of the work being performed, such as ATOMIC COPY
for atomic copy I/O and RELAYOUT for an online relayout
operation. The state is a single letter representing the task state:
R for running, P for paused, and K for aborting.
In the special case of the completion of a task that is being
monitored, the state is printed as EXITING. - 4.
The percentage of the operation that has been completed to this point. - 5.
The task's progress information. For basic tasks, this is the starting
offset, ending offset and current offset for the operation, separated
by slashes (/). For parent tasks, this is the starting number of
child tasks, total number of child tasks required for the operation to
complete, and the number of child tasks already completed to this
point, separated by slashes, followed by the number of children
currently running in parentheses. - 6.
A description of the command for which the task is performing
work. This is normally a single word, such as START for a volume
start operation or RELAYOUT for an online relayout, followed by
object names, indicating what the arguments were for the command. See
EXAMPLES below.
The long output format prints all available information for a task,
spanning multiple lines. If more than one task is printed, the output
for different tasks is separated by a single blank line. Each line in
the long output format contains a title for the line, followed by a
colon (:), followed by the information. The possible
information printed for a task includes:
- Operation:
A description of the operation on whose behalf the work is being
performed. This is essentially a description of the command executed
along with the VxVM objects specified as arguments. - Progress:
A description of the progress of the task. The progress is stated as a
percentage of completion, along with the actual progress values for
the task. - Started:
The time that the task was started. - Task:
General information for the task. The task's ID, followed by its
parent's ID (if any) in parentheses, followed by the task's state,
either RUNNING, PAUSED or ABORTING. - Throttle
The throttle value for the task, if applicable. - Type:
The task type, describing the work being performed. - Work time:
States how much time has been spent performing the work, and a rough
estimate of the time remaining for the task to complete.
As a special case, when a task being monitored completes only the
Task: line is printed for the task, with the task state
represented by EXITED. EXAMPLESTo list all tasks currently running on the system:
To trace all tasks in the diskgroup foodg that are currently
paused, as well as any tasks with the tag sysstart:
vxtask -g foodg -p -i sysstart list To list all tasks on the system that are currently paused:
To monitor all tasks with the tag myoperation:
vxtask monitor myoperation To cause all tasks tagged with recovall to exit:
FILES- /dev/vx/info
Used to get task information from the kernel. - /dev/vx/taskmon
Task monitoring device.
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