Nic resource going down frequently
We are experiencing below mentioned faults every now and then that affects our backup.
setup is like we have BkupLan service group in which we have NIC resource (bkup_nic) and Phantom resource .
Two service groups OSSfs and sybase1 have proxy resource monitoring this NIC resource.
and both are configured with Ip resources Ossbak_ip1 and sybbak_ip1.
The issue is Nic resource failed with below message and in turn proxy and ip resources failed.
Then NIC comes back and proxy and ip come back too.
Below is the configuration too
Please advice why it goen offline/online frequently
2013/10/24 22:32:03 VCS WARNING V-16-10001-7506 (ossadm2) NIC:bkup_nic:monitor:Resource is offline. No Network Host could be reached
2013/10/24 22:32:03 VCS INFO V-16-2-13716 (ossadm2) Resource(bkup_nic): Output of the completed operation (monitor)
==============================================
Broken Pipe
==============================================
2013/10/24 22:32:03 VCS ERROR V-16-1-10303 Resource bkup_nic (Owner: Unspecified, Group: BkupLan) is FAULTED (timed out) on sys ossadm2
2013/10/24 22:32:03 VCS INFO V-16-6-0 (ossadm2) resfault:(resfault) Invoked with arg0=ossadm2, arg1=bkup_nic, arg2=ONLINE
2013/10/24 22:32:03 VCS INFO V-16-0 (ossadm2) resfault:(resfault.sh) Invoked with arg0=/ericsson/core/cluster/scripts/resfault.sh, arg1=ossadm2 ,arg2=bkup_nic2013/10/24 22:32:03 VCS INFO V-16-6-15002 (ossadm2) hatrigger:hatrigger executed /opt/VRTSvcs/bin/triggers/resfault ossadm2 bkup_nic ONLINE successfully
2013/10/24 22:32:20 VCS ERROR V-16-1-10303 Resource ossbak_p1 (Owner: Unspecified, Group: Ossfs) is FAULTED (timed out) on sys ossadm2
2013/10/24 22:32:20 VCS NOTICE V-16-1-10300 Initiating Offline of Resource ossbak_ip (Owner: Unspecified, Group: Ossfs) on System ossadm2
2013/10/24 22:32:20 VCS ERROR V-16-1-10303 Resource syb1bak_p1 (Owner: Unspecified, Group: Sybase1) is FAULTED (timed out) on sys ossadm2
2013/10/24 22:32:20 VCS INFO V-16-6-0 (ossadm2) resfault:(resfault) Invoked with arg0=ossadm2, arg1=ossbak_p1, arg2=ONLINE
2013/10/24 22:32:20 VCS INFO V-16-0 (ossadm2) resfault:(resfault.sh) Invoked with arg0=/ericsson/core/cluster/scripts/resfault.sh, arg1=ossadm2 ,arg2=ossbak_p1
2013/10/24 22:32:20 VCS INFO V-16-6-0 (ossadm2) resfault:(resfault) Invoked with arg0=ossadm2, arg1=syb1bak_p1, arg2=ONLINE
2013/10/24 22:32:20 VCS INFO V-16-0 (ossadm2) resfault:(resfault.sh) Invoked with arg0=/ericsson/core/cluster/scripts/resfault.sh, arg1=ossadm2 ,arg2=syb1bak_p1
2013/10/24 22:32:20 VCS INFO V-16-6-15002 (ossadm2) hatrigger:hatrigger executed /opt/VRTSvcs/bin/triggers/resfault ossadm2 ossbak_p1 ONLINE successfully
2013/10/24 22:32:20 VCS INFO V-16-6-15002 (ossadm2) hatrigger:hatrigger executed /opt/VRTSvcs/bin/triggers/resfault ossadm2 syb1bak_p1 ONLINE successfully
2013/10/24 22:32:22 VCS INFO V-16-1-10305 Resource ossbak_ip (Owner: Unspecified, Group: Ossfs) is offline on ossadm2 (VCS initiated)
2013/10/24 22:33:04 VCS INFO V-16-1-10299 Resource bkup_nic (Owner: Unspecified, Group: BkupLan) is online on ossadm2 (Not initiated by VCS)
2013/10/24 22:33:04 VCS NOTICE V-16-1-10447 Group BkupLan is online on system ossadm2
2013/10/24 22:33:20 VCS INFO V-16-1-10299 Resource syb1bak_p1 (Owner: Unspecified, Group: Sybase1) is online on ossadm2 (Not initiated by VCS)
2013/10/24 22:33:20 VCS INFO V-16-1-10299 Resource ossbak_p1 (Owner: Unspecified, Group: Ossfs) is online on ossadm2 (Not initiated by VCS)
====================================================================================
ossadm2{root} # hastatus -summ
-- SYSTEM STATE
-- System State Frozen
A ossadm1 RUNNING 0
A ossadm2 RUNNING 0
-- GROUP STATE
-- Group System Probed AutoDisabled State
B BkupLan ossadm1 Y N ONLINE
B BkupLan ossadm2 Y N ONLINE
B DDCMon ossadm1 Y N ONLINE
B DDCMon ossadm2 Y N ONLINE
B Oss ossadm1 Y N OFFLINE
B Oss ossadm2 Y N ONLINE
B Ossfs ossadm1 Y N OFFLINE
B Ossfs ossadm2 Y N ONLINE
B PrivLan ossadm1 Y N ONLINE
B PrivLan ossadm2 Y N ONLINE
B PubLan ossadm1 Y N ONLINE
B PubLan ossadm2 Y N ONLINE
B StorLan ossadm1 Y N ONLINE
B StorLan ossadm2 Y N ONLINE
B Sybase1 ossadm1 Y N ONLINE
B Sybase1 ossadm2 Y N OFFLINE
you have mail
ossadm2{root} # hagrp -resources BkupLan
bkup_nic
bkup_p
ossadm2{root} # hagrp -resources bkup_nic
VCS WARNING V-16-1-12130 Group bkup_nic does not exist
ossadm2{root} # hagrp -resources BkupLan
bkup_nic
bkup_p
ossadm2{root} # hares -display bkup_nic
#Resource Attribute System Value
bkup_nic Group global BkupLan
bkup_nic Type global NIC
bkup_nic AutoStart global 1
bkup_nic Critical global 0
bkup_nic Enabled global 1
bkup_nic LastOnline global ossadm2
bkup_nic MonitorOnly global 0
bkup_nic ResourceOwner global
bkup_nic TriggerEvent global 0
bkup_nic ArgListValues ossadm1 Device 1 oce12 PingOptimize 1 1 NetworkHosts 1 127.0.0.1 Protocol 1 IPv4 NetworkType 1 ether ExclusiveIPZone 1 0
bkup_nic ArgListValues ossadm2 Device 1 oce12 PingOptimize 1 1 NetworkHosts 1 127.0.0.1 Protocol 1 IPv4 NetworkType 1 ether ExclusiveIPZone 1 0
bkup_nic ConfidenceLevel ossadm1 100
bkup_nic ConfidenceLevel ossadm2 100
bkup_nic ConfidenceMsg ossadm1
bkup_nic ConfidenceMsg ossadm2
bkup_nic Flags ossadm1
bkup_nic Flags ossadm2
bkup_nic IState ossadm1 not waiting
bkup_nic IState ossadm2 not waiting
bkup_nic MonitorMethod ossadm1 Traditional
bkup_nic MonitorMethod ossadm2 Traditional
bkup_nic Probed ossadm1 1
bkup_nic Probed ossadm2 1
bkup_nic Start ossadm1 0
bkup_nic Start ossadm2 0
bkup_nic State ossadm1 ONLINE
bkup_nic State ossadm2 ONLINE
bkup_nic ComputeStats global 0
bkup_nic ExclusiveIPZone global 0
bkup_nic NetworkHosts global 127.0.0.1
bkup_nic NetworkType global ether
bkup_nic PingOptimize global 1
bkup_nic Protocol global IPv4
bkup_nic TriggerResStateChange global 0
bkup_nic ContainerInfo ossadm1 Type Name Enabled
bkup_nic ContainerInfo ossadm2 Type Name Enabled
bkup_nic Device ossadm1 oce12
bkup_nic Device ossadm2 oce12
bkup_nic MonitorTimeStats ossadm1 Avg 0 TS
bkup_nic MonitorTimeStats ossadm2 Avg 0 TS
bkup_nic ResourceInfo ossadm1 State Stale Msg TS
bkup_nic ResourceInfo ossadm2 State Stale Msg TS
ossadm2{root} # hares -display bkup_p
#Resource Attribute System Value
bkup_p Group global BkupLan
bkup_p Type global Phantom
bkup_p AutoStart global 1
bkup_p Critical global 1
bkup_p Enabled global 1
bkup_p LastOnline global ossadm1
bkup_p MonitorOnly global 0
bkup_p ResourceOwner global
bkup_p TriggerEvent global 0
bkup_p ArgListValues ossadm1 ""
bkup_p ArgListValues ossadm2 ""
bkup_p ConfidenceLevel ossadm1 100
bkup_p ConfidenceLevel ossadm2 100
bkup_p ConfidenceMsg ossadm1
bkup_p ConfidenceMsg ossadm2
bkup_p Flags ossadm1
bkup_p Flags ossadm2
bkup_p IState ossadm1 not waiting
bkup_p IState ossadm2 not waiting
bkup_p MonitorMethod ossadm1 Traditional
bkup_p MonitorMethod ossadm2 Traditional
bkup_p Probed ossadm1 1
bkup_p Probed ossadm2 1
bkup_p Start ossadm1 1
bkup_p Start ossadm2 1
bkup_p State ossadm1 ONLINE
bkup_p State ossadm2 ONLINE
bkup_p ComputeStats global 0
bkup_p TriggerResStateChange global 0
bkup_p ContainerInfo ossadm1 Type Name Enabled
bkup_p ContainerInfo ossadm2 Type Name Enabled
bkup_p MonitorTimeStats ossadm1 Avg 0 TS
bkup_p MonitorTimeStats ossadm2 Avg 0 TS
bkup_p ResourceInfo ossadm1 State Stale Msg TS
bkup_p ResourceInfo ossadm2 State Valid Msg TS
ossadm2{root} # hagrp -resources Sybase1
sybasedg
sybmaster_mount
syblog_mount
sybdata_mount
pmsyblog_mount
pmsybdata_mount
fmsyblog_mount
fmsybdata_mount
dbdumps_mount
syb1_ip
syb1_p1
syb1bak_ip
syb1bak_p1
masterdataservice
masterdataservice_BACKUP
stop_sybase
ossadm2{root} # hares -display syb1bak_p1
#Resource Attribute System Value
syb1bak_p1 Group global Sybase1
syb1bak_p1 Type global Proxy
syb1bak_p1 AutoStart global 1
syb1bak_p1 Critical global 0
syb1bak_p1 Enabled global 1
syb1bak_p1 LastOnline global ossadm2
syb1bak_p1 MonitorOnly global 0
syb1bak_p1 ResourceOwner global
syb1bak_p1 TriggerEvent global 0
syb1bak_p1 ArgListValues ossadm1 TargetResName 1 bkup_nic TargetSysName 1 "" TargetResName:Probed 1 1 TargetResName:State 1 2
syb1bak_p1 ArgListValues ossadm2 TargetResName 1 bkup_nic TargetSysName 1 "" TargetResName:Probed 1 1 TargetResName:State 1 2
syb1bak_p1 ConfidenceLevel ossadm1 0
syb1bak_p1 ConfidenceLevel ossadm2 0
syb1bak_p1 ConfidenceMsg ossadm1
syb1bak_p1 ConfidenceMsg ossadm2
syb1bak_p1 Flags ossadm1
syb1bak_p1 Flags ossadm2
syb1bak_p1 IState ossadm1 not waiting
syb1bak_p1 IState ossadm2 not waiting
syb1bak_p1 MonitorMethod ossadm1 Traditional
syb1bak_p1 MonitorMethod ossadm2 Traditional
syb1bak_p1 Probed ossadm1 1
syb1bak_p1 Probed ossadm2 1
syb1bak_p1 Start ossadm1 0
syb1bak_p1 Start ossadm2 0
syb1bak_p1 State ossadm1 ONLINE
syb1bak_p1 State ossadm2 ONLINE
syb1bak_p1 ComputeStats global 0
syb1bak_p1 ResourceInfo global State Stale Msg TS
syb1bak_p1 TargetResName global bkup_nic
syb1bak_p1 TargetSysName global
syb1bak_p1 TriggerResStateChange global 0
syb1bak_p1 ContainerInfo ossadm1 Type Name Enabled
syb1bak_p1 ContainerInfo ossadm2 Type Name Enabled
syb1bak_p1 MonitorTimeStats ossadm1 Avg 0 TS
syb1bak_p1 MonitorTimeStats ossadm2 Avg 0 TS
ossadm2{root} # hares -display syb1bak_ip
#Resource Attribute System Value
syb1bak_ip Group global Sybase1
syb1bak_ip Type global IP
syb1bak_ip AutoStart global 1
syb1bak_ip Critical global 0
syb1bak_ip Enabled global 1
syb1bak_ip LastOnline global ossadm1
syb1bak_ip MonitorOnly global 0
syb1bak_ip ResourceOwner global
syb1bak_ip TriggerEvent global 0
syb1bak_ip ArgListValues ossadm1 Device 1 oce12 Address 1 10.41.78.138 NetMask 1 255.255.255.224 Options 1 "" ArpDelay 1 1 IfconfigTwice 1 1 RouteOptions 1 "" PrefixLen 1 0 ExclusiveIPZone 1 0
syb1bak_ip ArgListValues ossadm2 Device 1 oce12 Address 1 10.41.78.138 NetMask 1 255.255.255.224 Options 1 "" ArpDelay 1 1 IfconfigTwice 1 1 RouteOptions 1 "" PrefixLen 1 0 ExclusiveIPZone 1 0
syb1bak_ip ConfidenceLevel ossadm1 100
syb1bak_ip ConfidenceLevel ossadm2 0
syb1bak_ip ConfidenceMsg ossadm1
syb1bak_ip ConfidenceMsg ossadm2
syb1bak_ip Flags ossadm1
syb1bak_ip Flags ossadm2
syb1bak_ip IState ossadm1 not waiting
syb1bak_ip IState ossadm2 not waiting
syb1bak_ip MonitorMethod ossadm1 Traditional
syb1bak_ip MonitorMethod ossadm2 Traditional
syb1bak_ip Probed ossadm1 1
syb1bak_ip Probed ossadm2 1
syb1bak_ip Start ossadm1 1
syb1bak_ip Start ossadm2 0
syb1bak_ip State ossadm1 ONLINE
syb1bak_ip State ossadm2 OFFLINE
syb1bak_ip Address global 10.41.78.138
syb1bak_ip ArpDelay global 1
syb1bak_ip ComputeStats global 0
syb1bak_ip ExclusiveIPZone global 0
syb1bak_ip IfconfigTwice global 1
syb1bak_ip NetMask global 255.255.255.224
syb1bak_ip Options global
syb1bak_ip PrefixLen global 0
syb1bak_ip ResourceInfo global State Stale Msg TS
syb1bak_ip RouteOptions global
syb1bak_ip TriggerResStateChange global 0
syb1bak_ip ContainerInfo ossadm1 Type Name Enabled
syb1bak_ip ContainerInfo ossadm2 Type Name Enabled
syb1bak_ip Device ossadm1 oce12
syb1bak_ip Device ossadm2 oce12
syb1bak_ip MonitorTimeStats ossadm1 Avg 0 TS
syb1bak_ip MonitorTimeStats ossadm2 Avg 0 TS
ossadm2{root} # hares -display ossbak_p1
#Resource Attribute System Value
ossbak_p1 Group global Ossfs
ossbak_p1 Type global Proxy
ossbak_p1 AutoStart global 1
ossbak_p1 Critical global 0
ossbak_p1 Enabled global 1
ossbak_p1 LastOnline global ossadm2
ossbak_p1 MonitorOnly global 0
ossbak_p1 ResourceOwner global
ossbak_p1 TriggerEvent global 0
ossbak_p1 ArgListValues ossadm1 TargetResName 1 bkup_nic TargetSysName 1 "" TargetResName:Probed 1 1 TargetResName:State 1 2
ossbak_p1 ArgListValues ossadm2 TargetResName 1 bkup_nic TargetSysName 1 "" TargetResName:Probed 1 1 TargetResName:State 1 2
ossbak_p1 ConfidenceLevel ossadm1 0
ossbak_p1 ConfidenceLevel ossadm2 0
ossbak_p1 ConfidenceMsg ossadm1
ossbak_p1 ConfidenceMsg ossadm2
ossbak_p1 Flags ossadm1
ossbak_p1 Flags ossadm2
ossbak_p1 IState ossadm1 not waiting
ossbak_p1 IState ossadm2 not waiting
ossbak_p1 MonitorMethod ossadm1 Traditional
ossbak_p1 MonitorMethod ossadm2 Traditional
ossbak_p1 Probed ossadm1 1
ossbak_p1 Probed ossadm2 1
ossbak_p1 Start ossadm1 0
ossbak_p1 Start ossadm2 0
ossbak_p1 State ossadm1 ONLINE
ossbak_p1 State ossadm2 ONLINE
ossbak_p1 ComputeStats global 0
ossbak_p1 ResourceInfo global State Stale Msg TS
ossbak_p1 TargetResName global bkup_nic
ossbak_p1 TargetSysName global
ossbak_p1 TriggerResStateChange global 0
ossbak_p1 ContainerInfo ossadm1 Type Name Enabled
ossbak_p1 ContainerInfo ossadm2 Type Name Enabled
ossbak_p1 MonitorTimeStats ossadm1 Avg 0 TS
ossbak_p1 MonitorTimeStats ossadm2 Avg 0 TS
ossadm2{root} # hares -display ossbak_ip
#Resource Attribute System Value
ossbak_ip Group global Ossfs
ossbak_ip Type global IP
ossbak_ip AutoStart global 1
ossbak_ip Critical global 0
ossbak_ip Enabled global 1
ossbak_ip LastOnline global ossadm2
ossbak_ip MonitorOnly global 0
ossbak_ip ResourceOwner global
ossbak_ip TriggerEvent global 0
ossbak_ip ArgListValues ossadm1 Device 1 oce12 Address 1 10.41.78.137 NetMask 1 255.255.255.224 Options 1 "" ArpDelay 1 1 IfconfigTwice 1 1 RouteOptions 1 "" PrefixLen 1 0 ExclusiveIPZone 1 0
ossbak_ip ArgListValues ossadm2 Device 1 oce12 Address 1 10.41.78.137 NetMask 1 255.255.255.224 Options 1 "" ArpDelay 1 1 IfconfigTwice 1 1 RouteOptions 1 "" PrefixLen 1 0 ExclusiveIPZone 1 0
ossbak_ip ConfidenceLevel ossadm1 0
ossbak_ip ConfidenceLevel ossadm2 100
ossbak_ip ConfidenceMsg ossadm1
ossbak_ip ConfidenceMsg ossadm2
ossbak_ip Flags ossadm1
ossbak_ip Flags ossadm2
ossbak_ip IState ossadm1 not waiting
ossbak_ip IState ossadm2 not waiting
ossbak_ip MonitorMethod ossadm1 Traditional
ossbak_ip MonitorMethod ossadm2 Traditional
ossbak_ip Probed ossadm1 1
ossbak_ip Probed ossadm2 1
ossbak_ip Start ossadm1 0
ossbak_ip Start ossadm2 1
ossbak_ip State ossadm1 OFFLINE
ossbak_ip State ossadm2 ONLINE
ossbak_ip Address global 10.41.78.137
ossbak_ip ArpDelay global 1
ossbak_ip ComputeStats global 0
ossbak_ip ExclusiveIPZone global 0
ossbak_ip IfconfigTwice global 1
ossbak_ip NetMask global 255.255.255.224
ossbak_ip Options global
ossbak_ip PrefixLen global 0
ossbak_ip ResourceInfo global State Stale Msg TS
ossbak_ip RouteOptions global
ossbak_ip TriggerResStateChange global 0
ossbak_ip ContainerInfo ossadm1 Type Name Enabled
ossbak_ip ContainerInfo ossadm2 Type Name Enabled
ossbak_ip Device ossadm1 oce12
ossbak_ip Device ossadm2 oce12
ossbak_ip MonitorTimeStats ossadm1 Avg 0 TS
ossbak_ip MonitorTimeStats ossadm2 Avg 0 TS
ossadm2{root} # hatype -display NIC
#Type Attribute Value
NIC AEPTimeout 0
NIC ActionTimeout 30
NIC AgentClass TS
NIC AgentDirectory
NIC AgentFailedOn
NIC AgentFile
NIC AgentPriority 0
NIC AgentReplyTimeout 130
NIC AgentStartTimeout 60
NIC AlertOnMonitorTimeouts 0
NIC ArgList Device PingOptimize NetworkHosts Protocol NetworkType ExclusiveIPZone
NIC AttrChangedTimeout 60
NIC CleanRetryLimit 0
NIC CleanTimeout 60
NIC CloseTimeout 60
NIC ConfInterval 600
NIC ContainerOpts RunInContainer 0 PassCInfo 1
NIC EPClass -1
NIC EPPriority -1
NIC ExternalStateChange
NIC FaultOnMonitorTimeouts 4
NIC FaultPropagation 1
NIC FireDrill 0
NIC IMF Mode 0 MonitorFreq 1 RegisterRetryLimit 3
NIC IMFRegList
NIC InfoInterval 0
NIC InfoTimeout 30
NIC LevelTwoMonitorFreq 0
NIC LogDbg
NIC LogFileSize 33554432
NIC MonitorInterval 60
NIC MonitorStatsParam Frequency 0 ExpectedValue 100 ValueThreshold 100 AvgThreshold 40
NIC MonitorTimeout 120
NIC NumThreads 10
NIC OfflineMonitorInterval 60
NIC OfflineTimeout 300
NIC OfflineWaitLimit 0
NIC OnlineClass -1
NIC OnlinePriority -1
NIC OnlineRetryLimit 0
NIC OnlineTimeout 300
NIC OnlineWaitLimit 2
NIC OpenTimeout 60
NIC Operations None
NIC RestartLimit 0
NIC ScriptClass TS
NIC ScriptPriority 0
NIC SourceFile /etc/VRTSvcs/conf/config/types.cf
NIC SupportedActions device.vfd clearNICFaultInZone
NIC ToleranceLimit 0
NIC TypeOwner
I am surprised this works at all. You should not specify 127.0.0.1 for NetworkHosts - this should either blank, in which cast the broadcast address is pinged and a response is required from a host other than itself, but it is recommended to populate this attribute with at least one IP that is always there, like a router or a DNS server (you should NOT specify host IPs of other nodes in the cluster).
See extract from VCS Bundled agents guide:
List of hosts on the network that are pinged to determine if thenetwork connection is alive. You can use this attribute to help to savenetwork capacity and reduce monitor time. Symantec recommendsthat you use the outgoing gateway routers for this value.Enter the IP address of the host, instead of the host name, to preventthe monitor from timing out. DNS causes the ping to hang. If morethan one network host is listed, the monitor returns ONLINE if at leastone of the hosts is alive.If an invalid network host address is specified or if there is mismatchin protocol of network host and Protocol attribute of the resource, theresource enters an UNKNOWN state. If you do not specify networkhosts, the monitor tests the NIC by sending pings to the broadcastaddress on the NIC.Mike
Hello Symsonu,
yes, loopback device should always be pingable.
But, with setting loopback device as networkhost you break the whole concept of network monitoring in VCS.
You need to set an IP adress that is on the same network to ensure that the network connection is healthy.
If you set loopback address and network breaks VCS won't take corrective actions.
Regading the fault itself.
Did you check the syslog for any NIC events?
Setting loopback device doesn't change anything if the NIC is down on the OS level.
The loopback device is a virtual device that is NOT related to any NIC!
eth4 Link encap:Ethernet HWaddr 00:50:56:05:28:DD
inet addr:192.168.50.101 Bcast:192.168.50.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:718589 errors:0 dropped:0 overruns:0 frame:0
TX packets:735891 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:48433810 (46.1 Mb) TX bytes:55185850 (52.6 Mb)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:25664 errors:0 dropped:0 overruns:0 frame:0
TX packets:25664 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:4940075 (4.7 Mb) TX bytes:4940075 (4.7 Mb)
In the example above, if for example eth4 is down on the OS level VCS will take corrective action even though localhost is still reachable via ping command.
My guess is that you will either see some link down or NIC down messages in the syslog during the time of the fault.
Again, Networkhosts setting is used to detect network failures on a higher level.
For example if your connection from the NIC to the switch is healthy the link will be up, but if the link from the switch to the remote host is broken your network is broken.
Networkhosts is used to detect this kind of failures.
Thanks and kind regards,
Dan
