[Samba] TCP/IP block size

Jeremy Allison jra at samba.org
Tue Aug 5 15:30:31 GMT 2008

On Mon, Aug 04, 2008 at 10:18:37PM -0400, Jeremy M wrote:
> > 
> > If it returns 1300 bytes for a few times, then reduces the block size, then 
> > I'm going to guess that the TCP/IP stack on your microcontroller is giving 
> > Samba some clue that it's having trouble keeping up.
> > 
> > >It appears that Samba is transmitting data in chunks of 4K, and if I
> > 
> > How does it appear so? You have Wireshark on it? If Samba/Linux is sending 
> > 4k, then why did you say you're getting 512, 1024, or 1104? I'm not sure I 
> > understand your question.
> > 
> Let me clarify.  First, yes, I'm using Wireshark; troubleshooting would be a nightmare without it.  
> About the 4K thing: it looks like, and I could be wrong, that when I request sequential packets of data from a file, Samba/OS/whatever pulls 4K off the drive and feeds that 4K block to me, and *does not* send TCP packets that contains data which spans across blocks.  

That's usually because the Windows client is asking for a 4k
read. We can do up to 127k reads in "standard" SMB, but the
Windows clients don't ask for that.


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