Device down on SNMP but syslog works

Hello All !
We have a network of Cisco switches polled but we have frequently problems on SNMP.
The devices are up and working but LibreNMS show them as down for 20 minuts.
The syslog alerts are still received by LibreNMS so there is no IP connectivity problem between switches and LibreNMS.
Why LibreNMS alerts for device UP/Down if the ping is OK ?
How can I check if the problem is on server or on switches (Most probably on the server, the switches are all updates and recent)…

Thank you for your help.

The default rule looks at SNMP/ICMP for marking a device down.

You can change it up if you and do something like this with two separate alert rules.

Device Down %macros.device_down = "1" && %devices.status_reason = "icmp"

and

SNMP not responding on Device - Check on SNMP Service - %macros.device_down = "1" && %devices.status_reason = “snmp”

for this part could be a number of things i suggest you look at the performance doc to start Home - LibreNMS Docs

Hello Kevin,

Thank you for your time!
I have added the device.status_reason on my alert rule to only alert when icmp is dead!
I also have disbled many modules to have less diskIO.

Hope that it will do the trick!
Thanks.