manual:config:triggers:prediction
Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision Next revision | Previous revision | ||
|
manual:config:triggers:prediction [2015/10/12 08:47] glebs.ivanovskis [2.3 Threshold to reach] fixed syntax in examples |
manual:config:triggers:prediction [2018/10/01 09:42] (current) |
||
|---|---|---|---|
| Line 1: | Line 1: | ||
| - | ==== 8 Predictive trigger functions ==== | + | ==== 7 Predictive trigger functions ==== |
| === Overview === | === Overview === | ||
| Line 27: | Line 27: | ||
| (**timeleft** only)\\ Parameter ''threshold'' specifies a value the analysed item has to reach, no difference if from above or from below. Once we have determined f(t) (see below) we should solve equation f(t) = ''threshold'' and return the root which is closer to now and to the right from now or 999999999999.9999 if there is no such root. | (**timeleft** only)\\ Parameter ''threshold'' specifies a value the analysed item has to reach, no difference if from above or from below. Once we have determined f(t) (see below) we should solve equation f(t) = ''threshold'' and return the root which is closer to now and to the right from now or 999999999999.9999 if there is no such root. | ||
| - | <note tip>When item values approach the threshold and then cross it, **timeleft** assumes that intersection is already in the past and therefore switches to the next intersection with ''threshold'' level, if any. Best practice should be to use predictions as a complement to ordinary problem diagnostics, not as a substitution.((For example, a simple trigger like <code>{host:item.timeleft(1h,,X)} < 1h</code> may go into problem state when the item value approaches X and then suddenly recover once value X is reached. If the problem is item value being below X use: <code>{host:item.last} < X or {host:item.timeleft(1h,,X)} < 1h</code> If the problem is item value being above X use: <code>{host:item.last} > X or {host:item.timeleft(1h,,X)} < 1h</code>))</note> | + | <note tip>When item values approach the threshold and then cross it, **timeleft** assumes that intersection is already in the past and therefore switches to the next intersection with ''threshold'' level, if any. Best practice should be to use predictions as a complement to ordinary problem diagnostics, not as a substitution.((For example, a simple trigger like <code>{host:item.timeleft(1h,,X)} < 1h</code> may go into problem state when the item value approaches X and then suddenly recover once value X is reached. If the problem is item value being below X use: <code>{host:item.last()} < X or {host:item.timeleft(1h,,X)} < 1h</code> If the problem is item value being above X use: <code>{host:item.last()} > X or {host:item.timeleft(1h,,X)} < 1h</code>))</note> |
| == - Fit functions == | == - Fit functions == | ||