Memory Usage graph reports error when >68 hosts are selected

Neither Load Average nor any other graph I have been able to check has problems excluding Memory Usage.

The problem is present even in fullscreen mode.

Could you dump HAR file again?
now in fullscreen mode

Here is the link: [url]https://drive.google.com/file/d/0B5FL9q-xRjLJVUxJRVlDU2lPcEU/view?usp=sharing[/url]

I will be traveling most of next week, so I don’t know if I will be able to answer your message.

Thanks a lot

it is old one :frowning:
can you make completely new dump with fail?

Sorry, I sent the link in a rush. Here is the correct one:

[url]https://drive.google.com/file/d/0B5FL9q-xRjLJVkN5c3NtTWhfa0k/view?usp=sharing[/url]

Hi ac2,

it is fully empty :frowning: size is 0 bytes

Sorry, the file was created on a remote connection while traveling


I have been back from holidays and generated a new file: [url]https://drive.google.com/file/d/0B5FL9q-xRjLJWFc4WEZfQTI5RzA/view?usp=sharing[/url]

Could you please check this?

is this issue connected to exact host or to any random 68 hosts?

can you choose first 67 hosts in the list without issues?
can you choose last 67 hosts in the list without issues?
can you choose 67 hosts in the middle of the list without issues?

Hi Mykola,
actually I made a mistake while counting, the critical threshold is 68, sorry for that. Basically, the memory graph works correctly with 68 hosts selected (top, bottom, middle or punched card style doesn’t matter), fails with 69 onwards.
I have tested version 1.1.1 without any luck, too.

Thanks

is 59 mysql instances ran in 19 servers? or you have 78 independent servers?

lets check if we can fetch graph data directly from prometheus
http://PMM-SERVER-IP/prometheus/graph?g0.range_input=12h&g0.stacked=0&g0.expr=node_memory_MemTotal&g0.tab=0
http://PMM-SERVER-IP/prometheus/graph?g0.range_input=12h&g0.stacked=0&g0.expr=node_memory_MemFree&g0.tab=0
http://PMM-SERVER-IP/prometheus/graph?g0.range_input=12h&g0.stacked=0&g0.expr=node_memory_Buffers&g0.tab=0
http://PMM-SERVER-IP/prometheus/graph?g0.range_input=12h&g0.stacked=0&g0.expr=node_memory_Cached&g0.tab=0

We have 58 MySQL instances running on 16 MySQL VM, plus the PMM server is monitored, of course.

I have tried to access data directly in Prometheus and I see all the metrics for all nodes without any trouble, hence the issue seems related to Grafana.

Playing around selecting and deselecting hosts from the list, the problem appears “around” 68 hosts. Depending on the set, sometimes 67 is enough to trigger the problem, other times you need 69. So, it does not seem to be related to the number of hosts rather than the data volume to be accessed.

Thanks

  1. do you see any javascript errors in the browser javascript console?
  2. can you decrease resolution to 1/10
    it is needed to
  • login to grafana as Admin user
  • click on graph title
  • click “Edit”
  • choose “Metrics” tab
  • change Resolution value

see screenshot

Sorry for the very late reply, been very busy during the past days.
I have tried all the possible resolutions for the Memory trend graph, but I still get the error when >~68 hosts are selected from the list.

can you open “Developer Tools”->“Console” in your browser and reload page.
do you see any javascript errors?

I have the following JS messages on the Console:

TypeError: Cannot read property ‘result’ of undefined
at eval (datasource.js?bust=1488533087258:4)
at f (boot.b8fccc44.js:52)
at Function.Pg (boot.b8fccc44.js:53)
at eval (datasource.js?bust=1488533087258:4)
at g (boot.b8fccc44.js:42)
at boot.b8fccc44.js:42
at o.$eval (boot.b8fccc44.js:42)
at o.$digest (boot.b8fccc44.js:42)
at o.$apply (boot.b8fccc44.js:42)
at boot.b8fccc44.js:42
(anonymous) @ boot.b8fccc44.js:42
(anonymous) @ boot.b8fccc44.js:41
g @ boot.b8fccc44.js:42
(anonymous) @ boot.b8fccc44.js:42
$eval @ boot.b8fccc44.js:42
$digest @ boot.b8fccc44.js:42
$apply @ boot.b8fccc44.js:42
(anonymous) @ boot.b8fccc44.js:42
f @ boot.b8fccc44.js:40
(anonymous) @ boot.b8fccc44.js:41
boot.b8fccc44.js:46

Panel data error: TypeError: Cannot read property ‘result’ of undefined
at eval (datasource.js?bust=1488533087258:4)
at f (boot.b8fccc44.js:52)
at Function.Pg (boot.b8fccc44.js:53)
at eval (datasource.js?bust=1488533087258:4)
at g (boot.b8fccc44.js:42)
at boot.b8fccc44.js:42
at o.$eval (boot.b8fccc44.js:42)
at o.$digest (boot.b8fccc44.js:42)
at o.$apply (boot.b8fccc44.js:42)
at boot.b8fccc44.js:42

can you replace Query?

it is needed to

  • login to grafana as Admin user
  • click on graph title
  • click “Edit”
  • choose “Metrics” tab
  • fully replace Query value
100 - 100 * node_memory_MemAvailable{instance=~"$host"} / (node_memory_MemTotal{instance=~"$host"} + 0.1)

I have replaced the query with the new one you sent me. In this case I see the graph only for the host “pmm-server” when All is ticked in the hosts list.

Am I doing something wrong?

To be clearer, here is a screenshot:

Hm :frowning:
screen shot looks very strange, new Query working fine on my machine :frowning:

can you try again to change “Resolution” and “Query” after that press “save Dashboard” button (looks like floppy disk) and make refresh.

I tried various combinations of changing query and resolution, with no luck so far.
Selecting a subset of hosts (excluding pmm-server) is basically returning no data points, while with the original query I get a graph displayed. Please check the attached screenshot.