Zabbix dashboard is showing resolved problems

[moshikoy]

Hi,
During the last couple of weeks Zabbix is acting weird,
1. The dashboard is showing problems that were resolved

for example, I'm seeing host named host1 alerting that Zabbix agent is unreachable on it
while if i go to the zabbix server and run: zabbix_get -s host1 -k agent.ping
I get an answer: 1, which means that the zabbix agent is up and running and the zabbix server can see it.

Any idea what is happening?


Details:
Zabbix v3.4.1
Zabbix server is running Yes localhost:10051
Number of hosts (enabled/disabled/templates) 279 169 / 6 / 104
Number of items (enabled/disabled/not supported) 20803 18137 / 2034 / 632
Number of triggers (enabled/disabled [problem/ok]) 14484 13030 / 1454 [191 / 12839]
Required server performance, new values per second 177.14


Zabbix server graphs

https://imgur.com/a/u4ADn

- Moshe

[LenR]

Check the host interface ip or dns (whichever is used to monitor the host), make sure that is the same value or resolves to the same ip as your zabbix_get.

look at all latest data for the host, is it current?

[moshikoy]

I checked the IP/DNS and it is correct. no issues there.
Moreover this is not just a single host, I received these "fake" alerts on 30 different and unrelated hosts at around the same time.

I checked latest data for several of the hosts that have an open problem saying that the "zabbix agent is unreachable" (with duration of more than 24h)
and latest data is showing up-to-date data, gathered a few minutes ago.

Also, the dashboard is still active and new problems are being added and resolved. just not these ones.

I suspect the network was saturated at the time, and it caused alerts not to be closed. I just don't know how i can prove it.


- Moshe