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→Network checksumming
== Network checksumming ==
RHEL 5 based kernel supports IP checksum offload.
If network ethernet cards in your host support IP checksum offload then you can switch it features this feature on also for the virtual network devices (venet, veth). To check current offload setting for the hardware ethernet card (eth0, for instance) type # ethtool -k eth0 Make sure that tx/rx features are switched on.
To see current offload settings for the venet0 device, type
# ethtool -k venet0
To set offload settings off for the venet0 device, type
# ethtool -K venet0 tx on sg on
To set offload settings on for the venet0 device, type
# ethtool -K venet0 tx on off sg off Note, that 'tx on/off' enables/disables both tx and rx checksumming features for the all venet devices for all VEs and HN.
The same applies to the veth deviceexcept that 'tx on/off' enables/disables tx and rx checksumming features for only given virtual ethernet device in HN and corresponding VE.
== Shell scripts performance improvement ==
