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I'm using bosun to monitor my servers.

One strange problem is that in its default configuration it is reporting absurd figures for disk space. For example on one of my servers it says the root partition is 440% free. The true figure is about 51%.

In examining this I've found that the linux.disk.fs.space_total metric is returning twice the correct size of my disk...

[root@my-host-name ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1      8.0G  3.9G  4.2G  49% /

Bosun/scollector claim:

linux.disk.fs.space_total{environment=staging,host=my-host-name,role=gordo}: 16.10907G

Strangely the measurement of space used is still correct:

linux.disk.fs.space_used{environment=staging,host=my-host-name,role=gordo}: 4.36486G

I haven't given scollector any weird settings for its filesystem stuff. Can anyone give me a pointer towards getting the correct figures?

Software versions are:

[root@my-host-name ~]# /opt/go/bin/scollector -version
scollector version 0.3.0-dev

root@bosun:/data/bosun# /opt/bosun-linux-amd64 -version
bosun version 0.3.0 (9386abc03b9d074e42dbbe5eb5944ee88ca641f6) built 2015-07-13T15:17:11Z
Alex Hewson
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1 Answers1

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With Bosun default's time series databases, OpenTSDB, any tags you don't supply will be aggregated. So I think why you are getting values you don't expect because you didn't specify any value for the mount tag:

enter image description here

vs the following, where * is provided as the value to the mount tag:

enter image description here

Kyle Brandt
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  • If this isn't the problem, maybe you found a bug. The code that gathers disk stats is at `https://github.com/bosun-monitor/bosun/blob/master/cmd/scollector/collectors/disk_linux.go`, It gathers these stats from the df command: `"df", "-lP", "--block-size", "1"` – Kyle Brandt Aug 10 '15 at 13:04
  • Thanks @kyle, that makes more sense. If I select '/' for the `disk` tag I get the correct value. One UI difference is that in your screenshot the `*` is explicit but in mine the 'disk' field is left empty. Showing `*` makes it more obvious that an aggregation is taking place. Is that an improvement since 0.3.0? – Alex Hewson Aug 10 '15 at 14:00
  • @AlexHewson You have it backwards in that last comment, when you put `*` there is *no* aggregation taking place. When fields are blank, they are aggregated. If can think of a sensible way to show this in the GUI, create a GH issue suggesting how to indicate that. – Kyle Brandt Aug 10 '15 at 14:48