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Re: NFS file copy vs. snort ???


From: Michael D Schleif <mds () helices org>
Date: Sun, 5 Sep 2004 16:04:37 -0500

* Jason <security () brvenik com> [2004:09:05:16:01:51-0400] scribed:
Michael D Schleif wrote:

One of my main systems is connected to several NFS v3 servers; and, this
box also runs snort.

Copies, like the following examples, are excruciatingly slo-o-o-o-w-w-w,
especially when the file is large (e.g., 250 MiB.)

    cp -a /remote/tmp/* .
    cp -a * /remote/tmp/

By `slow', I mean in the two-digit kbps ;<

I do not find anything interesting in `vmstat', nor in
/var/log/{kern.log,messages,syslog}, nor is snort logging anything, in
this regard.

My first clue was noticing snort in `top' alternating in the top 2 or 3
positions.  Stopping snort on *both* ends of the connection results in file
transfers that meet my expectations.

What is going on with this?

How can I configure snort to *not* interfere with NFS?

What do you think?

I doubt Snort is interfering directly with your copy but instead you are 
using under powered hardware for the task of serving NFS and running 
snort.

Please, expand.  What constitutes ``under powered hardware'' in this
context?  See below.

It sounds like Snort is using all CPU so your NFS copies are 
slow...

No, it is *not* ``using all CPU''.  Load is typically between 1 and 2;
snort is typically using 2030% CPU; and other processes behave
un-impaired.

try tuning snort.

Actually, that is one of the things I was asking `how to do' when I
asked:

    How can I configure snort to *not* interfere with NFS?

Please, expand with something specific.

-- 
Best Regards,

mds
-
Dare to fix things before they break . . .
-
Our capacity for understanding is inversely proportional to how much
we think we know.  The more I know, the more I know I don't know . . .
--

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