CIFS over WAN

greghaa69 — Thu, 05 Jun 2025 05:48:13 GMT

We have a filer running 8.1.2p1 I think.

Locally CIFS gets about 120 mb a sec. Quite fast a definitely good performance.

Over a WAN however CIFS gets all of 130 KB a sec.

We have looked at the common items. Enabled SMB2, no signing, increased the TCP window for CIFS.

We have even set flow control on the switch side to on for both send and receive. However, no matter what

we do the performance will not get better than 130 KB a sec.

When we do tests to a Win 2008 R2 machine over the same link we get 20 Mbytes a sec on a 200 Mbit link.

Latency is ok, 53 ms rtt. That isn't awful or anything.

Is there anything we could be missing? The WAN link goes from CA to TX. We have netapps at both ends

and have test both way to multiple netapps all with the same outcome. I have also tested from CA to Atlanta GA

with roughly the same numbers.

Any thoughts would be appreciated.

Re: CIFS over WAN

nigelg1965 — Tue, 10 Dec 2013 14:32:55 GMT

Look at WAN accelerator products, like Riverbed?

greghaa69 — Tue, 10 Dec 2013 14:38:03 GMT

I am pretty sure a riverbed is already in use.

What I have discovered, is that over the WAN, the client gets a TCP window on 143,

where the NetApp is advertising a TCP window of 64240. Which is what we have

cifs.tcp_window_size set to.