Performance Tuning advice [just diag advices]

Jan Kratochvil short at
Sat Nov 14 17:47:40 GMT 1998

> On Fri, 13 Nov 1998 servis at wrote:
> Okay - a search of the digest archives on the Samba WWW pages didn't
> turn up anything real recent - I'll have to browse last months digest I
> guess.  But a search of the newsgroup archives at turned up
> some stuff. I've tried adding "SO_RCVBUF=4096 SO_SNDBUF=4096" to my

  Tried to increase them further? Maximum should be 32767/65535 depending
on your 'IP: Allow large windows (not recommended if <16Mb of memory)'
CONFIG_SKB_LARGE kernel configuration parameter.

  The best thing to diagnose such performance problems is to use tcpdump
to see the TCP flow control - I have experience that this is commonly
a problem in Samba environment. Please use either Samba NON-capable tcpdump
or use:
  tcpdump -i eth0|grep '^[0-9]'
to discard SMB protocol dissasembly (which is not useful for this). Also
you should see (with Samba capable tcpdump) whether all the data transaction
are done by RAW commands and their size is 65535 (maximum). And also
use strace to smbd to see how large and which read/write operations from/to
kernel are being made to remove wasteful userland/kernelland switching,
if any.
  If you have any difficulties on the previous command output understanding,
please feel free to contact me.

			Looking forward for M$ blow away,

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