[mdlug] Maxing out on 10/100 LAN

[Dan Pritts]

I wasn't entirely clear below about "samba chattiness."  the smb protocol 
does lots of conversations back and forth, it looks kind of like this:

send data
ask did you get it
wait for positive answer
send more data

this is at the SMB protocol layer, which is stupid because TCP already does it
for you .  but that's how it works.

I'm sure there is tuning you can do on this but i've never done it.

first, i assume that you are all in the same building or local campus.  if not, 
then note that network latency can drastically slow SMB file access - that chattiness
really kills you there.

so if i were you i'd do something like this:

sniff the network or just time some transfers to see whether you are saturating the
LAN.

if not, confirm you can saturate the LAN with a simple FTP.  if you can't, figure out 
why, wiring or switch problems, crappy ethernet cards, whatever.

next, troubleshoot samba / smb until you have gotten the best you can.  

since you have multiple concurrent users you can probably gain some throughput 
by increasing the connection speed of your server.    you probably only have a 10/100
switch, but see if it can do LACP (or cisco etherchannel).  If you can, you can hook up
multiple ethernet cards and have them act as a single logical ethernet.  see the 
wikipedia article for details of how this works.

If not, you need a new switch.  buy something with a 1G uplink that you can use for
your server.   The cheapest switch is not the best.  i like HP.  the 2510 is a decent little
switch for $250 for 24 ports.   They also have 1G versions, POE, etc. etc.  if you do buy
HP i recommend you stick to "e-series" ; "a-series" came via an acquisition and i've not
heard good things.

Put a decent 1GE card in your server.  The $100 one is really better than
the $25 one.

I like intel, see 

http://www.intel.com/content/www/us/en/network-adapters/gigabit-network-adapters/ethernet-server-adapters.html

On Sep 26, 2011, at 9:09 AM, Robert Adkins II wrote:

> We do a great of CAD/CAM work and the files that we are receiving as well as
> the resulting work files has been creeping up in the size over the past 10
> years.
> 
> It's not uncommon to have multiple operators hitting 20MB to 250+MB files
> simultaneously.
> 
> Sometimes, the operators are complaining about the speed of file access,
> etc., etc.
> 
> I want to speed that up a little.
> 
> Of course, I will need to do some testing to verify that they are saturating
> the link.
> 
> Regards,
> Robert Adkins 
> 
> 
> 
>> -----Original Message-----
>> From: mdlug-bounces at mdlug.org 
>> [mailto:mdlug-bounces at mdlug.org] On Behalf Of Dan Pritts
>> Sent: Thursday, September 22, 2011 9:37 PM
>> To: MDLUG's Main discussion list
>> Subject: Re: [mdlug] Maxing out on 10/100 LAN
>> 
>> assuming you are talking about general file service with 
>> moderate to large files, samba/smb chattiness is probably 
>> your limiting factor.
>> 
>> but make sure you are saturating the LAN before worrying 
>> about upgrading it.
>> 
>> I assume you have simultaneous active clients (if not, why 
>> worry about multiple interfaces?).  If so, you may see some 
>> improvement with a simple upgrade to a 10/100 switch with a 
>> couple 1G uplink ports, and put your server on 1G with a 
>> decent ethernet card.
>> 
>> 
>> Robert Adkins II wrote:
>>> That is along the lines I was thinking, unfortunately, to go to GB 
>>> ethernet, I do believe that I will need to rewire the whole 
>> building 
>>> and I am unsure if that will really fundamentally change 
>> performance 
>>> across the whole network. I certainly would need to acquire 
>> almost 30 
>>> Gigabyte Ethernet cards.
>>> 
>>> Perhaps I will dig around and setup samba to serve the same 
>> shares all 
>>> off a series of network interfaces.
>>> 
>>> Thanks.
>> 
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