Mailinglist Archive: opensuse (2483 mails)

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Re: [opensuse] slow nfs over wifi
On Sun, 2009-01-04 at 09:08 -0500, James Knott wrote:
Per Jessen wrote:
Per Jessen wrote:


lynn wrote:


Is wifi designed to be able to mount nfs shares?

I doubt if it was designed for it, but it works just fine.



I guess I should describe my own setup - everything is running on local
ethernet which is extended with a wireless LAN to which we connect with
laptops when not wokring in the office itself. The laptops use the NFS
shares from a central fileserver.



A lot of people have problems separating functions of the various system
components. WiFi is simply another physical layer, comparable to any
other, such as ethernet or token ring. That layer does not care about
content. Also, modern WiFi (802.11g or n) should be able to outrun most
personal internet connections, which are typically less than 10 Mb. An
802.11g signal has a maximum bandwidth of about 54 Mb/s, though that's
divided by more than half due to half duplex and other overhead. So,
bottom line, a properly functioning WiFi link should not have a
significant impact on throughput, when connecting over the internet,
regardless of protocols. My bet is on a flakey WiFi router or NIC in
the computer. In this instance, the hardware has some fault, which
prevents it from operating properly under load.


Comparing NFS (huge amount of large packets) with Internet access won't
do. A better (...) comparisson would be a large file transfer with sftp
or rsync. Large enough to have it going for several minutes. See if the
transfer rate is constant, or drops their also.

There are a lot of other factors to consider.
You might see five bars, indicating a strong signal, but are other on
the same channel?
When scanning fot open A.P. (ahum) i noticed that people seldom change
their pwd and even more seldom change their channel (probably 6 or 11)..
You might have five bars, but a dozen of your neighbours might see the
same amount .;)

Have a look with tcpdump: lot of re-transmissions?
Enable debugging/tracing in NFS (server-side)
Reducing MTU might also be helpfull

btw, no problems with a "wired" NFS-connection?

hw
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