Dell Intel PRO Family of Adapters User Manual
Page 82
NOTE: This setting is not saved across reboots. However this configuration change can be made permanent
through one of the following methods:
l
Add the following line to /etc/sysctl.conf:
net.ipv4.conf.all.arp_filter = 1
l
Install the interfaces in separate broadcast domains (either in different switches or in a switch partitioned
to VLANs).
Disable Rx Flow Control with ethtool
In order to disable receive flow control using ethtool, you must turn off auto-negotiation on the same command line. For
example:
ethtool -A eth? autoneg off rx off
Unplugging Network Cable While ethtool -p is Running
In kernel versions 2.5.50 and later (including 2.6 kernel), unplugging the network cable while ethtool -p is running will
cause the system to become unresponsive to keyboard commands, except for control-alt-delete. Restarting the system
appears to be the only remedy.
Detected Tx Unit Hang in Quad Port Adapters
In some cases, ports 3 and 4 do not pass traffic and report "Detected Tx Unit Hang" followed by "NETDEV
WATCHDOG: ethX: transmit timed out" errors. Ports 1 and 2 do not show any errors and will pass traffic.
This issue may be resolved by updating to the latest kernel and BIOS. It is encouraged to run an operating system that
fully supports MSI interrupts. This can be verified in your system BIOS by downloading the Linux Firmware Developer
Kit that can be obtained at
Do Not Use LRO when Routing Packets
Due to a known general compatibility issue with LRO and routing, do not use LRO when routing packets.
MSI-X Issues with Kernels Between 2.6.19 and 2.6.21 (inclusive)
Kernel panics and instability may be observed on any MSI-X hardware if you use irqbalance with kernels between
2.6.19 and 2.6.21. If these types of problems are encountered, you may disable the irqbalance daemon or upgrade to a
newer kernel.
Rx Page Allocation Errors
Page allocation failure order:0 errors may occur under stress with kernels 2.6.25 and above. This is caused by the way
the Linux kernel reports this stressed condition.
Enabling SR-IOV in a 32-bit Microsoft* Windows* Server 2008 Guest OS Using Intel®
82576-based GbE or Intel® 82599-based 10GbE Controller Under KVM
KVM Hypervisor/VMM supports direct assignment of a PCIe device to a VM. This includes traditional PCIe devices, as
well as SR-IOV-capable devices using Intel 82576-based and 82599-based controllers.
While direct assignment of a PCIe device or an SR-IOV Virtual Function (VF) to a Linux-based VM running 2.6.32 or
later kernel works fine, there is a known issue with Microsoft Windows Server 2008 VM that results in a "yellow bang"
error. This problem is within the KVM VMM itself, not the Intel driver, or the SR-IOV logic of the VMM, but rather that
KVM emulates an older CPU model for the guests, and this older CPU model does not support MSI-X interrupts, which
is a requirement for Intel SR-IOV.
If you wish to use the Intel 82576 or 82599-based controllers in SR-IOV mode with KVM and a Microsoft Windows
Server 2008 guest try the following workaround. The workaround is to tell KVM to emulate a different model of CPU
when using qemu to create the KVM guest:
"-cpu qemu64,model=13"