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

[Udo Rader]

On Wed, 2008-03-26 at 10:47 +0100, gianfranco pra floriani wrote:
> 
> 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.

doesn't look too bad.

> > 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.

Are you sure that it is a samba problem? Try to create a share on a WXP
LAN box and try to access it from a remote box.

Your problem is very likely a SMB (and not samba) problem.

And what type of OpenVPN adapter do you use? tun or tap?

-- 
Udo Rader

bestsolution.at EDV Systemhaus GmbH
http://www.bestsolution.at

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