[X-Unix] Re: Pokey LAN transfers (Resolved + a followup)

[Richard Hartman]

For those of you with interest in this goat rope, there has been a  
development that isn't surprising in hindsight; in fact most of you  
will simply think "well, duh!" But, for any other noobs struggling to  
make sense of it all, consider this:

I was having sporadic & bizarre trouble with DVD burns on my "system  
#2" MacBookPro (see below; running Leopard) and after much  
troubleshooting, tracked the problem down to some errant system &  
plist files.

The MBPro Leopard had been a clean install, not an upgrade, but it  
got a "migration assist" from my existing Tiger system. On the  
suspicion that the migration might have caused other issues, I erased  
& re-installed & updated Leopard on the MBPro, AND installed every  
necessary piece of software from scratch (i.e., NO migration).

Lo and behold, finder copies of the kind that formerly went at 25  
megabits per second are now shooting across at full speed (100 mbps).

So, although there was no indication in my console or system logs  
that anything was awry before the reinstall, in fact that pesky  
migration assistant evidently produced some sort of havoc. The Finder  
now copies as fast as rsync.

Moral, for me: Never, ever use migration assistant for major system  
upgrades; it oughta be a law...

Richard

On Dec 27, 2007, at 11:49 AM, Richard Hartman wrote:

> Thanks to Wing Wong, Nick Scalise, David Ledger and Brian Medley  
> for their thoughtful responses. For some reason, Wing Wong's  
> detailed response didn't make it to the list and is reproduced  
> (far) below.
>
> Here is a summary of what I learned:
>
> The overhead on my setup of mounting a volume on the desktop (via  
> AFP) is evidently enormous:
>
> - Mounting a LAN volume on the local desktop and then using cp on a  
> large (2GB) file using a terminal window (copying from mounted LAN  
> volume to internal disk drive)  produced transfer rates of only  
> about 25 megabits/sec.
>
> - Unmounting the LAN volume and instead using scp or rsync (and the  
> IP address of the source mac) produced the expected transfer rate  
> of 100 megabits/sec, which was the speed limit expected by the  
> slowest network element in the loop (the 100 mbps nic on one of the  
> macs).
>
> Regards,
>
> Rich
>
>> On Dec 26, 2007 1:54 PM, Richard Hartman < seasoft at west.net> wrote:
>> I'm looking for guidance on how best to copy large data sets between
>> macs on a network (Finder, terminal cp, other?).
>>
>> The setup: Copying from mac #1 (a 2006 iMac running 10.4.11 with
>> built-in 100bps ethernet) to mac #2 (a recent PBPro running 10.5.1
>> with built-in Gigabit ethernet). Macs connected by a Gigabit netgear
>> switch.
>>
>> I had hoped to get sustained transfers between these two macs of
>> 50-70 mbps (throttled by the rate-limiting 100 mbps iMac capability).
>>
>> However, copying a single 2 GByte file, by mounting the (Tiger) imac
>> on the (Leopard) MBPro desktop and using terminal "cp" command from
>> the MBPro terminal, results in a sustained transfer rate of only
>> about 2.5 mB/sec (25 mbps).
>>
>
>