Re: Routing 600+ vlan's via linux problems (looks like arp problems)

From: Øyvind Vågen Jægtnes
Date: Thu May 03 2007 - 17:12:28 EST


On 5/3/07, Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx> wrote:

On May 3 2007 22:53, Willy Tarreau wrote:
>> For the rest all we see in the arp cache is (incomplete)
>
>I suspect that your arp cache is full (128 entries by default).
>Check /proc/sys/net/ipv4/neigh/gc_thresh1 (128 for me). You can
>set it as high as gc_thresh2 (512 for me), and I don't know what
>happens above.

Above, you will perhaps need the not-so-elegant userspace arpd :-/

Yes, i was suspecting that the arp cache got full, but i will try
increasing it :)
Would there be any huge bugs if i change these lines in arp.c:

.gc_thresh1 = 128,
.gc_thresh2 = 512,

to

.gc_thresh1 = 700,
.gc_thresh2 = 700,

under the definition for struct arp_tbl?
This setup will only run for about 1-2 hours while we fix the hardware
router (it is running now, but only on a backup flash card solution.
the harddrive in it died ;)

I have been looking at arpd, but i quickly discarded it as an option
since its marked both experimental and obsolete ;)

regards
Øyvind Vågen Jægtnes
+47 96 22 03 08
lorrides@xxxxxxxxx
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