Re: Slow NFS Performance

Tom Eastep
Mon, 31 Mar 2008 18:47:54 -0000

roger wrote:
> I believe this is the second time I''ve encountered this issue
within the
> past 6 mos or more.  While performing some read/write tests between a
> NFS client and server, I noticed speed was severely hindered on my
> 100mbits network with tests of writing a ~17MB file taking ~15 minutes,
> of which, should only take ~8-10 seconds.

Is this with NFS over UDP or over TCP?
>
> After restarting Shorewall (firewall), speeds immediately returned to
normal.
> Steps I took to restart the server were "/etc/init.d/shorewall stop
&&
> shorewall clear && /etc/init.d/shorewall start".  (I was
trying to see if the
> configuration files were directly hindering performance.  Upon restarting
> shorewall, no further speed issues were noted.)
>
> This leads me to believe, Shorewall is borking someplace -- or more
correctly
> put, one of the kernel modules concerning Netfilter is failing??

Given that Shorewall isn''t something that runs continuously in your
system,
it''s hard to imagine that this problem is Shorewall-related.

>
> (Since this issue is extremely rare, it''s probably next to
impossible to
> debug, except on past experience from others.)
>
> Some bleak possibilities might include the use of Suspend to Disk (ie.
> TuxOnIce) and kexec (kernel reload).
>
>
> Here''s the requested debug info for this case scenario:

Better problem documentation would include:

a) Output of "shorewall dump" at the time that the problem was
encountered.
b) Output of "shorewall dump" after recovery measures were taken and
performance restored.

-Tom
--
Tom Eastep    \ Nothing is foolproof to a sufficiently talented fool
Shoreline,     \ http://shorewall.net
Washington USA  \ teastep@shorewall.net
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