[Slightly OT?] Performance of SMB over WANs

Richard Sharpe sharpe at ns.aus.com
Fri Mar 1 15:31:06 GMT 2002

Jason Haar wrote:

>We've got a knarly issue here, and I'm wondering if anyone here could help
>me understand it.
>Our company's WAN runs primarily over IPSec VPNs. Benchmarking shows
>Linux-to-Linux FTP/HTTP peaks at around 80% of the available Internet link
>over which the VPN operates - so that's looking pretty sweet.
>However, Microsoft networking runs at ***1/10th*** that amount! i.e. SMB
>transfers are a fraction of FTP transfer rates. 
>I originally thought this was a M$ stack issue, but then brought Samba in
>and benchmarked it on the same two Linux boxes used for the FTP tests - they
>had the same poor throughput.
>So, can anyone explain to me what's so different about SMB that would so
>radically affect it over a WAN link? I would have thought that after the
>initial auth/perms checks are done, the streaming of the data would approach
>FTP speeds...
SMB is a request response protocol, and things can go wrong. Have you 
got TCP_NODELAY off in your smb.conf file? It is the default.

Can you send us a trace of some of the activity?

>BTW, RH7.x Linux systems, transmitting 6Mb files.

Richard Sharpe, rsharpe at ns.aus.com, rsharpe at samba.org, sharpe at ethereal.com
www.samba.org, www.ethereal.com, SAMS Teach Yourself Samba 
in 24 Hours, Special Edition, Using Samba

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