Why SNMP request timeouts when NFS share on remote server is hanging

Issue

• snmpd freezes intermittently with timeout error

HOST-RESOURCES-MIB::hrStorageIndex.10 = INTEGER: 10   
Timeout: No Response from localhost

• We have a RHEL 6.5 Server which mounts an NFS share from remote. During the day it happens that the share is not responding. In addition our monitoring server polls via SNMP different metrics from this server and we have seen that during this hangs the SNMP requests from our monitoring server get a timeout. After a while (1-2 hours) everything works again.