[Samba] HELP! running 3.0.23c-2 on fedora core 6 strange slow speed problem

[Bill Fung]

Hi

i have experience deploying samba for several sites. Recently, i encounter a very strange problem. The site has been running samba and
sendmail on a server since nov 2006 and everything is fine. At mid Apr 2007, i add a new network interface eth1 for some reason:

BEFORE CHANGE
=============

  INTERNET
      ^
      |
|------------|
| ADSL MODEM |
|------------|
      ^
      |
|------------|
|   ROUTER1  |
|------------| 192.168.1.1
      ^
      |
|------------|-------
|   SWITCH   |------- XP CLIENTS (192.168.1.0/255.255.255.0)
|------------|-------
      ^
      |
|------------| eth0:192.168.1.2
|   SAMBA    |
|------------|


AFTER CHANGE
=============

  INTERNET
      ^
      |
|------------|
| ADSL MODEM |
|------------|
      ^
      |
|------------|
|   ROUTER1  |
|------------| 192.168.1.1
      ^
      |
|------------| eth1:192.168.1.2
|   SAMBA    |
|------------| eth0:192.168.2.2
      |
      v
|------------|-------
|   SWITCH   |------- XP CLIENTS (192.168.2.0/255.255.255.0)
|------------|-------
      |
      v
|------------| 192.168.2.1
|   ROUTER2  |
|------------|
      |
      v
|------------|
| ADSL MODEM |
|------------|
      |
      v
  INTERNET (VPN to remote site 192.168.0.0/255.255.255.0)

Simply speaking, samba/vpn traffic will go thru eth0 and email/other traffic will go thru eth0.
After the change, i encounter that the following strange situation:

1) copying files from XP clients to samba server is OK (no speed change, copy a 16mb file in less than 3 seconds)

2) copying files from samba share to XP clients is sometimes normal and somestimes very slow (copy a 16mb files take about 3 minutes), strange
enough, when in the progress of copying a large file (200mb), the traffic could be speed up by copying a smaller file (16mb) at the same time. In
this case, the 16mb file will be copied at normal speed (<3second), and you could observe the progress indicator of the 200mb file is speed up
during the copying of 16mb file. The progress indicator of the 200mb file will slow down again after copying the 16mb file.

Below is the routing table:
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.2.0     0.0.0.0         255.255.255.0   U     0      0       0 eth0 
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0       0 eth1 
192.168.0.0     192.168.2.1     255.255.255.0   UG    0      0       0 eth0 
169.254.0.0     0.0.0.0         255.255.0.0     U     0      0       0 eth1 
0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0       0 eth1

I add a specific route to remote site 192.168.0.0/255.255.255.0 thru vpn by /sbin/route add -net 192.168.0.0/24 gw 192.168.2.1 dev eth0

Here is what i try:
1) uninstall samba and install again, start newly install samba again with default config with minimal changes. problem persist!
2) replace switch with another new switch, problem persist!!
3) i start a ftp service on the samba server and verify the network speed is normal, implying that network card/switch has no problem

I guess the problem may be caused by:
1) routing problem
2) samba multiple interface problem
3) samba ip change from 192.168.1.2 to 192.168.2.2

For 2), I have man smb.conf and add the following to my smb.conf:
interfaces = 192.168.2.0/24
But problem still persist.

For 3), anyone have any hints on that? changing ip of samba server will cause problem??

Any help will be highly appreciated. Thanks a lot in advanced.



-- 
Regards,
Bill