CentOS - Jan 2015 - Question about Neighbour Table Overflow.

Hi, all

When use Centos 6.5,kernel version 2.6.431, I have continuous messages of
"Neighbour table overflow" in messages.
I have modified the gc_thresh1(512)  , gc_thresh2 (2048) gc_thresh3 (4096)
in /proc/sys/net.. path, But the messages occurs occasionally.

some forum saied:
They are probably realted to a kernel bug where the thresholds are in fact
only half of the value that is set. See
http://patchwork.ozlabs.org/patch/170385/
---

I didn't figure it out whether it is a bug and it is fixed . Why did this
happen?  Who can give me hand.

Thanks.

On Thu, Jan 08, 2015 at 11:38:46PM +0800, zhen wang
wrote:
> Hi, all
> 
> When use Centos 6.5,kernel version 2.6.431, I have continuous messages of
> "Neighbour table overflow" in messages.
> I have modified the gc_thresh1(512)  , gc_thresh2 (2048) gc_thresh3 (4096)
> in /proc/sys/net.. path, But the messages occurs occasionally.
We had 1,500 machines in our colo when I did this to stop those
complaints:

# increase the size of the neighbor tables to be more than the # of ips in the
colo
net.ipv4.neigh.default.gc_thresh1 = 2048
net.ipv4.neigh.default.gc_thresh2 = 2304
net.ipv4.neigh.default.gc_thresh3 = 2560

-- greg