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Diffstat (limited to '')
| -rw-r--r-- | health/REFERENCE.md | 38 |
1 files changed, 32 insertions, 6 deletions
diff --git a/health/REFERENCE.md b/health/REFERENCE.md index f1bb5557..66ccf88d 100644 --- a/health/REFERENCE.md +++ b/health/REFERENCE.md @@ -679,7 +679,7 @@ Check the `health/health.d/` directory for all alarms shipped with Netdata. Here are a few examples: -### Example 1 +### Example 1 - check server alive A simple check if an apache server is alive: @@ -739,7 +739,7 @@ If these result in non-zero or true, they trigger the alarm. So, the warning condition checks if we have not collected data from apache for 5 iterations and the critical condition checks for 10 iterations. -### Example 2 +### Example 2 - disk space Check if any of the disks is critically low on disk space: @@ -760,7 +760,7 @@ So, the `calc` line finds the percentage of used space. `$this` resolves to this This is a repeating alarm and if the alarm becomes CRITICAL it repeats the notifications every 10 seconds. It also repeats notifications every 2 minutes if the alarm goes into WARNING mode. -### Example 3 +### Example 3 - disk fill rate Predict if any disk will run out of space in the near future. @@ -803,7 +803,7 @@ Once this alarm triggers we will receive an email like this:  -### Example 4 +### Example 4 - dropped packets Check if any network interface is dropping packets: @@ -823,7 +823,7 @@ Note that the drops chart does not exist if a network interface has never droppe When Netdata detects a dropped packet, it will add the chart and it will automatically attach this alarm to it. -### Example 5 +### Example 5 - CPU usage Check if user or system dimension is using more than 50% of cpu: @@ -842,7 +842,7 @@ The `lookup` line will calculate the average CPU usage from system and user in t the foreach in the `lookup` line, Netdata will create two independent alarms called `dim_template_system` and `dim_template_user` that will have all the other parameters shared among them. -### Example 6 +### Example 6 - CPU usage Check if all dimensions are using more than 50% of cpu: @@ -860,6 +860,32 @@ lookup: average -3s percentage foreach * The `lookup` line will calculate the average of CPU usage from system and user in the last 3 seconds. In this case Netdata will create alarms for all dimensions of the chart. +### Example 7 - Z-Score based alarm + +Derive a "[Z Score](https://en.wikipedia.org/wiki/Standard_score)" based alarm on `user` dimension of the `system.cpu` chart: + +```yaml + alarm: cpu_user_mean + on: system.cpu +lookup: mean -60s of user + every: 10s + + alarm: cpu_user_stddev + on: system.cpu +lookup: stddev -60s of user + every: 10s + + alarm: cpu_user_zscore + on: system.cpu +lookup: mean -10s of user + calc: ($this - $cpu_user_mean) / $cpu_user_stddev + every: 10s + warn: $this < -2 or $this > 2 + crit: $this < -3 or $this > 3 +``` + +Since [`z = (x - mean) / stddev`](https://en.wikipedia.org/wiki/Standard_score) we create two input alarms, one for `mean` and one for `stddev` and then use them both as inputs in our final `cpu_user_zscore` alarm. + ## Troubleshooting You can compile Netdata with [debugging](/daemon/README.md#debugging) and then set in `netdata.conf`: |