# ovf-monitor command

The ovf-monitor command monitors and
displays overflow consumption on a port by port basis.

## Syntax

```
ovf-monitor {*|port{,port}{-port}...} {(options}
```

## Parameter(s)

| * | Monitors all ports. This is the default. | |
| --- | --- | --- |
| port{,port}{-port}...} | Specifies the port(s) or range of ports to monitor. | |
| options | a | Displays all target ports. By default, only the ports that are actively consuming overflow are displayed. |
| s | Enables scroll mode. Each new occurrence of activity is displayed as a new line in the output display. Note that older entries will scroll off the screen when the screen becomes full. | |
| tn | Specifies the time in n seconds between refreshes of the displayed ports. The default is 10 seconds. | |
Upon running ovf-monitor, a set of options
display at the bottom of the results:

```
Press 8=up; 2=down;7=home;1=end;9-PgUp;3=PgDn;ESC=Exit;Rtn=Refresh
```
The options allow you to move up and down through the
displayed results (not available when scrolling mode is enabled),
refresh the displayed results or exit the program.

## Example(s)

The example below illustrates
using the ovf-monitor command to display all target
pibs.

```
:ovf-monitor (a

Overflow Monitor 17:25:53
Port Ovf used Change Cached Change Cache Max Ports' Total
0 0 0 No cache 1838
1 57 0 14 0 30 1838
2 0 0 No cache 1838
3 45 0 15 0 30 1838
4 0 0 0 0 0 1838
5 0 0 0 0 0 1838
6 0 0 0 0 0 1838
7 0 0 0 0 0 1838
8 0 0 0 0 0 1838
9 0 0 0 0 0 1838
10 0 0 0 0 0 1838
11 0 0 0 0 0 1838
12 0 0 0 0 0 1838
13 0 0 0 0 0 1838
14 0 0 0 0 0 1838
15 0 0 0 0 0 1838
16 17 0 0 0 0 1838
17 823 0 0 0 0 1838
18 822 0 0 0 0 1838
Press 8=up; 2=down;7=home;1=end;9-PgUp;3=PgDn;ESC=Exit;Rtn=Refresh
```
Note: Negative values displayed in either the `Ovf used` or `Total` columns indicate a condition
where a port released more overflow frames than it consumed. For example,
if a user creates a file on port 1 and then subsequently deletes the
file using port 2, the port 2 `Ovf used` value would
display a negative number indicating the difference between the number
of overflow frames that have been released and consumed by that line.

The example below illustrates setting the ovf-monitor command to use a scrolling display that refreshes every 2 seconds.
In this case, only the activity on port 20 is being monitored.

```
:ovf-monitor 20 (st2

Overflow Monitor 17:25:53
Port Ovf used Change Cached Change Cache Max Ports' Total
20 23 23 3 3 30 1860
20 40 17 19 16 30 1877
20 0 -40 19 0 30 1837
20 0 -40 19 0 30 1837
20 0 -40 19 0 30 1837
20 0 -40 19 0 30 1837
20 0 -40 19 0 30 1837
20 0 -40 19 0 30 1837
20 1 0 0 -19 0 1838
20 0 0 0 -19 0 1837
20 0 0 0 -19 0 1837
20 0 0 0 -19 0 1837
20 0 0 0 -19 0 1837
20 0 0 0 -19 0 1837
20 0 0 0 -19 0 1837
20 23 23 3 3 30 1860
Press ESC=Exit;Rtn=Refresh
```

## See also

- [init-ovf command](https://d3codex.com/tcl/init-ovf-command/)
- [set-ovf-reserve command](https://d3codex.com/tcl/set-ovf-reserve-command/)
- [set-runaway-limit command](https://d3codex.com/tcl/set-runaway-limit-command/)
- [free command](https://d3codex.com/tcl/free-command/)
- [overflow command](https://d3codex.com/tcl/overflow-command/)

---
Source: https://d3codex.com/tcl/ovf-monitor-command/ - part of the D3Codex reference.