false positive Network unreachable

[trinkity]

At 4:00 AM for 2 hour i've serious problem with my server zabbix.
I received a lot of mail from all machine:
example
Server x Network unreachable: PROBLEM at 04:16
Server x Network unreachable: OK at 04:17

But the server x is always online.
This is my status network.


The average traffic network is about 7 Kb/s but i don't understand why at the 4 am the traffic change.

Sorry for my english

By andrea

[jroberson]

What does your System load and HDD load look like at that time. What do you have your "housekeeping" frequency set in the zabbix_server.conf file? I've noticed similar dips when my housekeeping cycle starts but never for as long as that.

[trinkity]

Was disabled by default.
Now i've enabled
HousekeepingFrequency=1
I reboot the service.
Now i see if the problem is solved

[trinkity]

The problem persist

Help me please!!!
I don't know what i do

[jroberson]

Do you notice any heavy load on your server at that time? More CPU usage, low usable RAM, heavy harddrive usage, high incoming network traffic, runaway process? There has to be some correlation there. For example: I notice a large spike in the CPU IOWait, User, and System times every hour when my housekeeping cycle starts. I also notice a spike in my HDD usage, memory usage and a small drop in network traffic at that same time . That last one is the one that led me to believe it might had something to do with your housekeeping cycle. Even after you look at all that, it could ultimately be something going on with the hosts you are monitoring at that time. Like a massive virus scan or defrag. There could still even be a network load issue at that time of day. It's pretty hard to diagnose the illness with only one of the symptoms.