[Samba] Poor performance on open/copy/close/rename file operations via remote/VPN connection

gianfranco pra floriani gian at nexta.com
Mon Mar 24 21:30:58 GMT 2008


Hello,
I have Samba version 3.0.24 running on a 2.6.14-gentoo-r5 x86 kernel 
(xeon 3ghz, 1gb ram raid 5).
All clients accessing samba shares via LAN have no problems. Samba 
server works perfectly and fast.
We are instead experiencing serious performance issues when accessing 
samba shares from remote clients (WAN), via VPN.
Simple operations like "open a file", "copy & paste a file", "save a 
file" from Windows XP SP2 clients are incredibly slow. It may take 10 
seconds to open a "save as" dialog box, and maybe 15 more seconds to 
save a "hello world" txt file from Notepad.
Other services using the VPN such as SCP, SSH, HTTP, FTP work very good 
on the same connection, with no slow issues at all. I tried 2 kinds of 
VPN connections (OpenVPN and a router-proprietary VPN 
gateway-to-client), and both have the same issue, both only with Samba.
I wonder if there is something I'm missing in client or server 
configuration that makes Samba talking very slow when connections are 
not coming from the LAN. The file transfer process works fine: once the 
"saving file" or "copying file" process has begun, it takes the same 
amount of time needed by a SCP or a FTP transfer command using the same 
VPN connection. I tried to copy a 2MB file from client to server and the 
time needed using SCP and using SAMBA (once the copy process was 
started) was the same.
I tried to add some "socket options = TCP_NODELAY SO_SNDBUF=8192 
SO_RCVBUF=8192" in smb.conf with no results.
The problem is the same using "explorer", command prompt, or any program 
in the client. We currently use all XP SP2 clients.
It looks like the initial and final talking acknowledgement between 
client and server for any kind of operation is unacceptably slow, while 
the file transfer process seems not to be involved in this problem.
Here is my smb.conf global parameters section:
# Global parameters
[global]
        workgroup = MYGROUP
        netbios name = MYSERVER
        server string = %h server (Samba %v)
        encrypt passwords = Yes
        obey pam restrictions = Yes
        passwd program = /usr/bin/passwd %u
        passwd chat = *Enter\snew\sUNIX\spassword:* %n\n 
*Retype\snew\sUNIX\spassword:* %n\n .
        syslog = 0
        log file = /var/log/samba/log.%m
        log level = 2
        max log size = 1000
        invalid users = root
        create mask = 0664
        directory mask = 0775

    
[homes]
        comment = Home Directories
        create mask = 0600
        directory mask = 0700
        browseable = No


[pdf]
        path = /tmp
        guest ok = Yes
        printable = Yes
        print command = /usr/bin/printpdf %s %u
        lpq command =
        lprm command =

[... shares defitinions omitted..]

Any kind of help will be really appreciated.
Thank you

Gianfranco Pra Floriani
Nexta Media - Italy



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