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#1 Packet loss in ARP monitoring mode

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nobody
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5
2002-11-22
2002-11-22
Anonymous
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We're building our system to meet the "no single point
of failure" requirement. Each server has two NICs and
each NIC is connected to a separate switch (see
attached drawing). We have chosen to use the bonding
driver to take care of the dual NIC failover. Bonding
works great if we connect the gigastack link between
the two switches and use the miimon option. But if we
disconnect the gigastack, which simulates a special
situation in our system, MII link status monitoring is
not enough. So we tried ARP monitoring and found it
problematic.

The FEP servers in the drawing are Dell PowerEdge 2550
running RedHat Linux 7.3. Bonding driver is already
loaded into the kernel. We did recompile ifenslave as
required in the howto document.

The following lines were added to /etc/modules.conf

alias bond0 bonding
options bond0 mode=1 miimon=100
arp_ip_target=192.168.53.1 arp_interval=5000

File "ifcfg-bond0" was created in
/etc/sysconfig/network-scripts with the following lines:

DEVICE=bond0
BOOTPROTO=none
BROADCAST=192.168.53.255
IPADDR=192.168.53.22
NETMASK=255.255.255.0
NETWORK=192.168.53.0
ONBOOT=yes

With this particular setup, we have found that we lose
about half of the packages when we do a ping, when both
nics are up and running. From "ifconfig" command, we
can't tell which one is active (no "NOARP" flag is seen).

I wonder if VRRP packets are required on the switches
in order for arp monitoring to work. It was mentioned
in the final section in the howto document.

I'd appreciate any help. Thank you!

Discussion

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  • Bob Schmertz
    Bob Schmertz
    2003-01-15

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    Hope that creating this comment will enable me to add a
    contact point for this bug.