Env:
Oracle ODA Appliance, which based on ORACLE VM Server set.
Dom0/Host: odahost1
Dom1/VM: odahostdb1
Problem:
use can not ssh onto Dom1/VM from outside ODA. ping is ok.
SSH will hang here:
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#ssh root@odahostdb1 ... ... debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP Connection closed by 10.191.6.55 |
From Dom0 /var/log/message:
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Nov 21 21:40:49 odahost1 last message repeated 2 times Nov 21 21:41:50 odahost1 last message repeated 7 times Nov 21 21:44:40 odahost1 kernel: bond0: received packets cannot be forwarded while LRO is enabled Nov 21 21:46:48 odahost1 last message repeated 16 times Nov 21 21:48:48 odahost1 last message repeated 8 times |
This problem is due to LRO of eth0 not disabled.
Although bond0 LRO is disabled by default, eth0 which bond0 is based on is not.
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[root@odahost1 ~]# ethtool -k bond0 | grep large-receive-offload large-receive-offload: off [root@odahost1 ~]# ethtool -k eth0 | grep large-receive-offload large-receive-offload: on |
Fix:
just disable LRO on eth0
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[root@odahost1 network-scripts]# ethtool -K eth0 lro off |
restart network service.
To make the changes permenant:
If Dom0/Host is EL5:
add following line to /etc/rc.local
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/sbin/ethtool -K eth0 lro off |
If Dom0/Host is EL6+:
add following line to ifcfg-eth0:
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ETHTOOL_OPTS="-K ${DEVICE} lro off" |
the problem on EL5/6 different fix is on initscripts package version.
EL6 with initscripts 9.03+ accepts this ETHTOOL_OPTS, but EL5 with initscripts 8.45 does not.
Refer:
Poor TCP Performance on VMs; dmesg:”received packets cannot be forwarded while LRO is enabled”