[Samba] Weird Samba upload performance on Gigabit network

David Harrison david.harrison at stress-free.co.nz
Thu Nov 9 22:31:18 GMT 2006

Here's a weird one that may have nothing to do with Samba and more to  
do with network frame sizes.

I have recently upgraded the network infrastructure to support  
gigabit speeds.

- OSX Tiger to OSX Tiger file transfers operate at gigabit speeds.
- Samba 3.0.23C (Suse 10) to OSX Tiger file transfers operate at  
gigabit speeds.
- BUT OSX Tiger to Samba 3.0.23C (Suse 10) file transfers operate at  
1-2meg/second which is well down from expected performance.

The strange thing is if I begin a file transfer from OSX Tiger to  
Samba and in a terminal window on OSX begin an SCP copy operation to  
the same Suse server the file transfer speed of Samba jumps up to  
gigabit level speeds. As soon as the SCP copy operation is stopped  
the Samba file transfer process drops to 1-2meg/second again.

My guess is this has something to do with network frame sizes but I  
don't really know.

The gigabit card on the Suse box is a low-end model but the fact that  
downloads and non-Samba related uploads appear to work fine (with low  
CPU usage in all cases) suggests this is more to do with inbound SMB  
packets rather than the hardware itself.

Any hints/pointers would be appreciated.



P.S. Sorry I thankfully do not have any 'real' Windows machines to  
test performance on.

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