[Samba] Dynamic Link Aggregation via Samba

Adam Nielsen adam.nielsen at uq.edu.au
Mon Oct 12 00:43:42 MDT 2009

> Do you have any idea why SMB on MAC would be half the speed than AFP? (
> As mentioned below). I.e. do you have any recommendations on better
> socket options or similar that could yield a higher speed over SMB?

In my experience SMB/CIFS is usually faster than other options (NFS in
my case) so AFP must be extremely efficient :-)

>>>>>> I have a gigabit NIC (network interface card) in my G5 on my desktop.
>>>>>> Gigabit is about 123 Megabytes per second per what I gathered on the
>>>>>> net. However when you have more users and traffic you can actually never
>>>>>> reach that full spectrum more like 40 MB/s. By adding Network interface
>>>>>> cards to my server and bonding them I was able to up the speed via
>>>>>> Appletalk up to about 90-100 Megabytes per second stably - closer to
>>>>>> home. However via SMB I was not able to get that speed increase.

I would start out by running ttcp (you can find the source freely
online) and do a proper benchmark just to see how much network bandwidth
you have available in an ideal case.

>>>>>> I literally copy the same file just using the other protocol and the
>>>>>> speed goes down. Then when I copy the file via AFP I get the expected
>>>>>> result.

Have you tried timing the copy time with a stopwatch and a large file?
Often the speeds reported by the OS can be questionable.

>>>>>> I was told it has to do with the socket options of SMB and how Samba
>>>>>> passes packets over to the TCP IP layer etc. So I increased the sendbuff
>>>>>> size on my CentOS server but this did not result in the increase I
>>>>>> expected. Still about 53 Megabytes per second. So I am looking for any
>>>>>> info on how to get max bandwidth over gigabit via Samba. I.e. other
>>>>>> settings that I need to tweak? Or maybe settings that I have to change
>>>>>> on my G5 in terminal? Any ideas?

Probably need to see what ttcp is reporting as available bandwidth
first, vs the real speeds you're getting (which you can work out from
the filesize and the stopwatch if you don't have anything more accurate.)

>>>>>> The server is capable of 250 Megabytes per second write speed that I am
>>>>>> trying to connect to. (that is not that fast but still faster than the
>>>>>> network speed.)

I assume nobody else is accessing the disk while you're performing the

>>>>>> PS: Are the pgms you mentioned available for Power PCs (the older
>>>>>> non-intel based macs? Also would they help me tweak Samba or more for
>>>>>> speed checking?

Both are open source and will compile anywhere Samba does.  It won't
help you tweak Samba but it will make it clear where you stand and if
you really do have a problem.


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