Arp Cache issue

[brian irvin]

Posting sysctl.conf

# cat /etc/sysctl.conf
# Kernel sysctl configuration file for Red Hat Linux
#
# For binary values, 0 is disabled, 1 is enabled.  See sysctl(8) and
# sysctl.conf(5) for more details.

# Controls IP packet forwarding
net.ipv4.ip_forward = 0

# Controls source route verification
net.ipv4.conf.default.rp_filter = 1

# Do not accept source routing
net.ipv4.conf.default.accept_source_route = 0

# Controls the System Request debugging functionality of the kernel
kernel.sysrq = 0

# Controls whether core dumps will append the PID to the core filename
# Useful for debugging multi-threaded applications
kernel.core_uses_pid = 1

# Controls the use of TCP syncookies
net.ipv4.tcp_syncookies = 1

# Controls the maximum size of a message, in bytes
kernel.msgmnb = 65536

# Controls the default maxmimum size of a mesage queue
kernel.msgmax = 65536

# Controls the maximum shared segment size, in bytes
kernel.shmmax = 68719476736

# Controls the maximum number of shared memory segments, in pages
kernel.shmall = 4294967296
kernel.sysrq = 1

# 
net.ipv4.tcp_fin_timeout = 60
net.ipv4.tcp_retries1 = 3
net.ipv4.tcp_keepalive_probes = 9
net.ipv4.tcp_keepalive_time = 1800
net.ipv4.tcp_syn_retries = 5
net.ipv4.tcp_orphan_retries = 3
 
Thanks

Brian

> -----Ursprüngliche Nachricht-----
> Von: redhat-list-bounces at redhat.com
> [mailto:redhat-list-bounces at redhat.com]
> Im Auftrag von Richardson, Joshua A.
> Gesendet: Mittwoch, 13. Juli 2011 16:18
> An: General Red Hat Linux discussion list
> Betreff: RE: Arp Cache issue
> 
> 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
> > unsubscribe mailto:redhat-list-request at redhat.com?subject=unsubscribe
> > https://www.redhat.com/mailman/listinfo/redhat-list
> > 
> 
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