On Tue, Sep 13, 2005 at 04:41:22PM -0400, Joshua Baker-LePain wrote:
> On Tue, 13 Sep 2005 at 10:20pm, Erik P. Olsen wrote
> 
> > On Tue, 2005-09-13 at 16:10 -0400, Joshua Baker-LePain wrote:
> > > We're talking about network bandwidth -- ethernet.  And the parameter is 
> > > there in case your backup server and/or clients perform other network 
> > > intensive functions that you don't want to interfere with.  Myself, I 
> > > consider backups most important and want amanda to use all the bandwidth 
> > > it can.
> > 
> > Yes and therefore a netuse value of "max" would be appropriate. I
> > understand from what you say that the lower the bandwidth the slower the
> > backup, but why does it make a full stop right before the backup
> > finishes? Well, it is probably more an academic question. I would,
> > however, like to get the answer but I will not read the code to get
> > it :-)
> 
> Amanda doesn't actually throttle the backups.  It looks at how much 
> bandwidth is being used (based on history and backups speeds IIRC, which I 
> may well not), and will refuse to start a new backup if the usage is > 
> netusage.

Just a clarification on terminology.

As your dump progresses, dumpers become available, the dumper has to be
assigned to some DLE, i.e. client/disk pair.  It is at this point that
amanda will decide to start a new dump or not, not the entire backup,
just whether to start any particular DLE dumping or not depending on
the current "network usage".

The slower backup does not come by slowing things down to the netusage
parameter.  It comes from only having fewer DLEs dumping over the network
at the same time.  Once they start they can actually use whatever network
bandwidth they want.  Amanda has no further control over it.  Just whether
to start it now or later.

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
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