[OpenAFS] Re: Server disk operations speed

Jukka Tuominen jukka.tuominen@finndesign.fi
Wed, 10 Apr 2013 20:51:36 +0300 (EEST)

> On Tue, 9 Apr 2013 23:36:15 +0300 (EEST)
> "Jukka Tuominen" <jukka.tuominen@finndesign.fi> wrote:
>> Does it sound resonable to prefer DNS names over external IP's, and
>> external IP's over local IP's? The rationale there would be to prefer
>> dynamic over static definitions, and IP's that the clients can see
>> over local IP's that may not be accessible always? (external meaning
>> WAN and internal LAN IP's). I've started with whatever worked, and
>> later on moved towards what I just described.
> I'm not quite sure if you're asking what you as a person should do, or
> if you're asking what the code does.
> If you mean what IPs you should be specifying in various places, you
> should put in the 'public' IPs that are always reachable by everyone.
> That means put that in CellServDB and probably the fileserver NetInfo.
> If you put a 'private' IP in there, then clients accessing from
> elsewhere may also see that IP, and obviously they won't be able to
> connect. We don't really do "split-horizon"-style setups, since everyone
> gets the same list of IPs for fileservers.

This answered my question. These are my initial findings with Wireshark:

When running wireshark on the idle server machine, there was no striking
errors that I could spot while browsing through the output. I then grepped
/etc/ for any private IP entries. Since the machine is on DMZ, it has a
private address in /etc/network/interfaces. /etc/openafs/server/CellServDB
and /etc/openafs/CellServDB were the only other ones. I changed the latter
two to public ones, but wireshark started to print "unreachable ports". It
seemed that /etc/openafs/server/CellServDB had to have the private IP in
place in order not to raise errors.

It also seems, that there is quite a frequent traffic between the private
and the public IP. I believe the traffic goes to the NIC at least, but
propably not further (hub, switch or firewall) but I can't say for sure.
Wireshark pairs the private and public, and then public and private on
single lines, so how is that interpreted?

I'd like to get rid of that noise because it may be _the_ problem, or at
least it won't speed up things for sure. I'm just not sure whether it is
possible from DMZ. Does anybody else have afs server on DMZ, and still get
the full speed. And if yes, then do you have a private or public IP

Or maybe I have just routed the traffic otherwise backwards, somehow...

br, jukka

>> If you just want to see where the traffic is
>> > going, capture some net traffic. All AFS traffic for a client
>> > interacting with a server should happen on ports 7000-7003 UDP. If
>> > we're contacting an IP that is one of the local host's interfaces,
>> > it's up to the underlying OS where the packets physically go.
>> OK, I'll try to figure out how to do that. Wireshark is my guess to
>> start with.
> Yes, tcpdump or wireshark are the usual tools. wireshark is/can be
> graphical and probably more intuitive if you haven't used similar tools
> before.
> --
> Andrew Deason
> adeason@sinenomine.net
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