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

[gianfranco pra floriani]

Udo Rader wrote:
> On Mon, 2008-03-24 at 22:30 +0100, gianfranco pra floriani wrote:
>   
>> 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.
>>     
>
> This is quite common with VPN connections. What response time do you get
> from a ping (LAN vs. VPN)?
>
>   
Hello Udo,
this is a ping from the server to a client:
PING 10.0.0.190 (10.0.0.190) 56(84) bytes of data.
64 bytes from 10.0.0.190: icmp_seq=1 ttl=128 time=52.7 ms
64 bytes from 10.0.0.190: icmp_seq=2 ttl=128 time=48.9 ms
64 bytes from 10.0.0.190: icmp_seq=3 ttl=128 time=49.2 ms
from client to server the ping time is the same.
> A major network performance for VPN clients is the correct configuration
> of various networking parameters (such as MTU, window size, etc. - all
> depending on the type of internet connection you have).
>
> And finally, what type of VPN are you using?
>
>   
we have ssh, scp, ftp and http services running on the same VPN  
(OpenVPN 2.0.6 i686-pc-linux-gnu), and all services are running fine, no 
delays, no bottlenecks. Samba is the only service having problems.

> Very probably you cannot do much about it from the samba side.
>
>