Amanda-Users

Re: broadcast traffic

2009-06-22 23:18:11
Subject: Re: broadcast traffic
From: Steve Wray <steve.wray AT cwa.co DOT nz>
To: "Dustin J. Mitchell" <dustin AT zmanda DOT com>
Date: Tue, 23 Jun 2009 15:08:27 +1200
Dustin J. Mitchell wrote:
On Tue, Jun 16, 2009 at 9:11 AM, Charlie Reitsma<reitsma AT denison DOT edu> 
wrote:
So, perhaps, the ISP is mistaking the backup traffic as a broadcast storm.
It would appear as a sudden spike of traffic leaving the server. If so, a
conversation with the ISP should clear up the issue.

Other possibilities:

The Amanda server or a client is accidentally configured with a
broadcast address (this can happen easily in the tiny subnets hosting
providers will often make for customers)

An ARP cache is broken somewhere, so every packet requires an ARP probe.

(Charlie, your suggestion is the simplest, but broadcast traffic is
usually counted and reported separately, so I suspect this may,
indeed, be broadcast)

I had seen some mention of broadcast being used by amanda to locate tape servers or something...

But this problem turned out to be a misconfiguration on one of the ISPs routers which was exacerbated by our amanda backup runs. They then proceeded to blame the backup process for the problem until I did a test run during the day while they were watching.

Fixed now.



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