The O (Overlay) command displays the current system overlay utilization statistics. It can also be used as a timed option for the ADM (Automatic Display Mode) command. For more detailed information, refer to ADM (Automatic Display Mode).
Syntax
Explanation
The O (Overlay) command displays the current system overlay utilization statistics, which include the amount and percentages of overlay disk usage and the system percentages for the overlay.
The statistics display has two parts: processor overlay utilization statistics and overlay disk utilization statistics.
Processor Overlay Utilization
There are three overlay components: the first is the overlay processor statistic, and the remaining two are the overlay system parameters. These overlay components are described in the following table.
|
Component |
Description |
|---|---|
|
System Usage |
The percentage of processor time that could not be used because of overlay activity. |
|
Threshold |
If the system parameter OLAYGOAL is 0 (zero) and the System Usage value is larger than the Threshold value, any new tasks are scheduled. You can change the Threshold value by setting the OLAYSATURATION factor in the SF (Set Factor) system command. |
|
Change per Second |
The smoothing factor used to determine current overlay activity. You can change this value by setting the OLAYCHANGE factor in the SF (Set Factor) system command. |
Overlay Disk Utilization
The following table explains the remaining factors in the Overlay Utilization report.
|
Component |
Description |
|---|---|
|
Allocated Overlays on Disk |
The percentage of Overlay Disk Allocated sectors that are currently holding data. |
|
Overlay Disk Allocated |
The percentage of Total Overlay Sectors that are allocated for use by overlayable arrays. |
|
Total Overlay Sectors |
The number of sectors reserved by the overlay subsystem. |
Example
OVERLAY
---------------------- OVERLAY UTILIZATION ------------------- System Usage = 8% Allocated Overlays on Disk = 62% Threshold = 15% Overlay Disk Allocated = 74% Change per Second = 10% Total Overlay Sectors = 246,389
