Arp Cache issue

[Richardson, Joshua A.]

Can you post your /etc/sysctl.conf file?  Maybe the answer resides in your arp cache size limits and garbage collection frequency?

Thanks!

Josh Richardson
General Dynamics AIS

-----Original Message-----
From: redhat-list-bounces at redhat.com [mailto:redhat-list-bounces at redhat.com] On Behalf Of brian irvin
Sent: Wednesday, July 13, 2011 9:34 AM
To: General Red Hat Linux discussion list
Subject: Re: Arp Cache issue

We are using bnx2 driver. We are getting outages when arp table fills up and unless we flush the table, network connectivity is an issue. 

more ifcfg-bond0
DEVICE=bond0
BONDING_OPTS="mode=1 miimon=500 primary=eth4"  


Thanks

Brian


--- On Tue, 7/12/11, Georgios Magklaras <georgios at biotek.uio.no> wrote:

> From: Georgios Magklaras <georgios at biotek.uio.no>
> Subject: Re: Arp Cache issue
> To: "General Red Hat Linux discussion list" <redhat-list at redhat.com>
> Date: Tuesday, July 12, 2011, 9:41 PM
> 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
> 
> -- redhat-list mailing list
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