Centos 6.6 - net-snmp unreponsive

Fredrik Björk

2014-12-28 12:57:37 UTC

Hi!

Just a thought: do the checks succeed or is the high number of open
files due to unsuccessful polls that keep hanging around retrying? If
so, try to decrease the timeout and number of retries. I think there are
often ridiculously high timeout limits in SNMP NMS software. Who wants a
reply if it's 5 seconds old? Set the timeout to 1 second (or even lower
if appropriate and possible) and set retries to 2 to 4. Figure out for
yourself if you want alerts if you lose two packets (2 retries only) or
not. I tend to use 1 sec timeout and 3 retries.

/Fredrik

Post by Laurent Dumont
Hi gents,
I have a CentOS 6.6 install with net-snmp running. I'm using SNMPv3 Auth
and Encryption with Observium polling devices every five minutes. On one
of my Centos server, the net-snmp process will die after 24-36 hours of
running. It seems to be hitting my system maximum file open limit which
is set to 1024.

1024
1071
snmpd 26907 root 166r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 167r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 168r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 169r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 170r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 171r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 172r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 173r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 174r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 175r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 176r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 177r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 178r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
snmpd 26907 root 179r REG 0,3 0 4026532160
/proc/26907/net/sctp/snmp
#tail /var/log/snmpd.log
cannot open /proc/net/dev ...
/proc/partitions: Too many open files
/proc/stat: Too many open files
/proc/partitions: Too many open files
/proc/stat: Too many open files
could not create socket
/proc/partitions: Too many open files
/proc/stat: Too many open files
cannot open /proc/net/dev ...
/proc/partitions: Too many open files
/proc/stat: Too many open files
/proc/partitions: Too many open files
/proc/stat: Too many open files

That number will keep increasing till it trips the 1024 limit. It seems
that CentOS is frozen to net-snmp 5.5 and I'm don't really want to use
anything that I can't easily manage with "yum". The weird thing is that
I have another server with the same config/CentOS version/Net-Snmp
version and I have no issues with the snmp process on that server.
Anything else I could try to troubleshoot the issue?
Thanks!
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