[Beowulf] Is it necessary to increase size of the ARP cache?

[Bart Jennings]

You could always write a script to capture the arp caches of some of 
your machines over time.  If your caches are constantly full, then 
increasing might be warranted. You also might want to consider looking 
at your arp cache timeout value since all that new space won't matter if 
it's gone before you need to use it.

On 5/27/2010 3:52 PM, Greg Lindahl wrote:
> On Thu, May 27, 2010 at 05:25:56PM -0500, Rahul Nabar wrote:
>
>    
>> But is there a way of knowing from logs etc. if this fix is indeed needed
>> for my network?
>>      
> If you tcpdump and see a crapload of arp broadcasts, you know.
>
>    
>> What is the effect of a suboptimal ARP cache size? Does that affect
>> the latency of messages too?
>>      
> It hurts latency because an arp reply has to come back before you can
> send your packet.
>
> -- greg
>
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