Volume pacing
The Volume Pacing section of the Performance Data panel displays information about volume pacing for current and past sessions.
| Field | Description |
|---|---|
| Volume Pacing | If volume pacing is active, the level of read operations that is in effect (15, 5, 3, and 1). If volume pacing is inactive, it is stated. |
| Percent of TDMF Copy Phase I/O | Shows the percentage of I/O operations that used 15 tracks, 5 tracks, 3 tracks, and 1 track in a single I/O operation during the copy phase. |
| Percent of TDMF Refresh Phase I/O | Shows the percentage of I/O operations that used 15 tracks, 5 tracks, 3 tracks, and 1 track in a single I/O operation during the refresh phase. |
| Number Pacing Changes Due to Real Storage Manager (RSM) | The number of pacing changes made due to RSM constraints. Note: The
amount of storage that is used automatically changes the number of tracks read/written in a single
I/O operation.
|
| Pacing Delay Due to I/O Contention | The amount of delay that is inserted between each TDMF I/O operation to provide more device availability. The delay is noted cumulatively and for the last interval. |
The following figure shows an example of volume pacing (if selected).
Volume Pacing Active using 15 Tracks per Operation.
--- T R A C K S ---
15 5 3 1
Percent of Copy Phase I/O using : 100 0 0 0
Percent of Refresh Phase I/O using :
Number Pacing Changes Due to Real Storage Manager.
Raise to : 0 0 0 0
Lower to : 0 0 0 0
Pacing Delay Due to I/O Contention Cumulative Last Interval
Pacing I/O Delay 00.000 Secs 0.00 msecIf reverse pacing was selected for the volume pairing, it is indicated at the beginning of the session on this panel, where the number of tracks per operation is 01. If the level of activity permits, TDMF increases the number of tracks that are read per I/O operation.