Arp Cache issue

[Georgios Magklaras]

On 07/12/2011 09:46 PM, brian irvin wrote:
> We have a RHEL 5 box which requires frequent flushing of arp cache to stay up and running and not create network bottlenecks. Anyone have these issues? we have quite a few servers and have never faced an issue before this one. I thought it might have to do with the switch but the network folks say the switch is clear. Any thoughts??
>
> cat /proc/net/bonding/bond0
> Ethernet Channel Bonding Driver: v3.4.0 (October 7, 2008)
>
> Bonding Mode: fault-tolerance (active-backup)
> Primary Slave: eth4
> Currently Active Slave: eth4
> MII Status: up
> MII Polling Interval (ms): 500
> Up Delay (ms): 0
> Down Delay (ms): 0
>
> Slave Interface: eth0
> MII Status: up
> Link Failure Count: 0
> Permanent HW addr: 00:37:c9:38:e3:3b
>
> Slave Interface: eth4
> MII Status: up
> Link Failure Count: 0
> Permanent HW addr: 00:11:17:4c:ee:22
>
>
> Thanks
>
> Brian.
>

Can you clarify a bit the staying up and running/bottleneck issue? What 
happens if you do not flush the ARP table in terms of what you see in 
the system and what do you see on the LAN side for the system? Also 
which Ethernet driver module you use in the system?

I have seen issues with IP aliasing (not HA bonding) on very busy LANs, 
but long time ago, not on recent 5 releases. As far as I know, unless 
you use a load balancing mode bonding, the netwrk switch should not be 
tweaked.


GM

-- 
-- 
George Magklaras PhD
RHCE no: 805008309135525

Senior Systems Engineer/IT Manager
Biotek Center, University of Oslo
EMBnet TMPC Chair

http://folk.uio.no/georgios

Tel: +47 22840535