Slowdown when copying large files

[Michael Anthon]

I am currently investigating using samba on a Linux box to provide file
server services on our NT LAN (I'm a bit sick of NT doing dummy spits on
me).  I'm running RH5.1, and have just upgraded samba to
samba-1.9.18p8-51.3 (using the rpm from
http://samba.anu.edu.au/samba/ftp/Binary_Packages/redhat/RPMS/5.1/samba-
1.9.18p8-51.3.i386.rpm)

The setup includes several NT servers, one set up as a PDC and 2 BDCs
and samba is confiigured to use the PDC for password authentication.

Everything seems to work fine, except that when I try copying a largeish
file (the test one I'm using is about 12M) it takes about 8-10 minutes
to copy (this is on a 10M LAN).  I ran top on the Linux box while I was
doing this and smbd seems to start off using around 8% of CPU time, but
at the point things seem to start slowing down, the usage jumps up to
75-80%.

I'm wondering if this is a known problem and if it's not, perhaps a few
pointers on where to start looking might help me a bit.

TIA
Michael Anthon

TAMS Systems