Antwort: Re: [hobbit] bbtest shows long DNS runtime, why

Fri Sep 12 17:04:06 CEST 2008

Thank you for the very quick answer! The testip tag did the trick. Now I 
again have a near-zero-line for the bbtest runtime.

Thorsten Erdmann
ITI/EP68
Mercedes Benz Werk Hamburg
Tel.: +49-40-7920-2593
mobil: +49-160-8614383
Lotus-Fax:+49-711-1779043874
mail: thorsten.erdmann at daimler.com

josh at imaginenetworksllc.com 
12.09.2008 15:43
Bitte antworten an
hobbit at hswn.dk

An
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Re: [hobbit] bbtest shows long DNS runtime, why

It seems that hobbit resolves all clients via DNS:   
  # hostnames resolved  :       40
Why that, I gave all names and it's corresponding IPs at the bb-hosts 
file?

www.google.com 208.69.36.230 #   <-- this will lookup www.google.com and 
ping the IP, if it can't find an A record for it then it will use the IP 
as a backup

www.google.com 208.69.36.230 #   testip <--- this will use the hostname 
for display purposes, no dns lookup and skip to using the IP for the conn 
test

I have the same triangular graphs on hotspot networks with multiple APs. 
This is normal, as far as I can tell.

Adding 400 hosts and 400 dns queries shouldn't cause too much of a load, 
though, if you're worried about the DNS queries taking out the DNS servers 
then just tack "testip" to the end of them.  The conn/ping test is awfully 
efficient, assuming you're using fping.

Are you using fping or hobbitping?

Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373

Those who don't understand UNIX are condemned to reinvent it, poorly.
--- Henry Spencer

On Fri, Sep 12, 2008 at 9:38 AM, <thorsten.erdmann at daimler.com> wrote:

Hi

I am running hobbit against 40 clients. Two of these clients are our DNS 
servers. Only on these two clients I have enabled the DNS test by adding 
the DNS keyword to their bb-hosts line. I wanted to check the function of 
the DNS servers

If I look at the statistics of bbtest it looks like this:

Fri Sep 12 15:26:08 2008

bbtest-net version 4.2.0
SSL library : OpenSSL 0.9.7a Feb 19 2003
LDAP library: OpenLDAP 20213

Statistics:
 Hosts total           :       41
 Hosts with no tests   :        1
 Total test count      :       44
 Status messages       :       45
 Alert status msgs     :        0
 Transmissions         :        2

DNS statistics:
 # hostnames resolved  :       40
 # succesful           :       40
 # failed              :        0
 # calls to dnsresolve :       44

TCP test statistics:
 # TCP tests total     :        2
 # HTTP tests          :        1
 # Simple TCP tests    :        1
 # Connection attempts :        2
 # bytes written       :      126
 # bytes read          :      871

TIME SPENT
Event                                            Starttime Duration
bbtest-net startup                       1221225968.275331 -
Service definitions loaded               1221225968.276931 0.001600 
Tests loaded                             1221225968.281365 0.004434 
DNS lookups completed                    1221225973.283037 5.001672 
Test engine setup completed              1221225973.285332 0.002295 
TCP tests completed                      1221225973.286398 0.001066 
PING test completed (40 hosts)           1221225974.166549 0.880151 
PING test results sent                   1221225974.177932 0.011383 
Test result collection completed         1221225974.177943 0.000011 
LDAP test engine setup completed         1221225974.177944 0.000001 
LDAP tests executed                      1221225974.177945 0.000001 
LDAP tests result collection completed   1221225974.177946 0.000001 
NSLOOKUP tests executed                  1221225974.179452 0.001506 
Test results transmitted                 1221225974.181039 0.001587 
bbtest-net completed                     1221225974.182936 0.001897 
TIME TOTAL 5.907605 

What you see are two mystic things:

It seems that hobbit resolves all clients via DNS:   
  # hostnames resolved  :       40
Why that, I gave all names and it's corresponding IPs at the bb-hosts 
file?

The DNS test runs about 5 seconds for only these 40 clients, maybe that is 
because of the first issue:  
  DNS lookups completed                    1221225973.283037 5.001672

If you look at the graph, it gives very scary "triagle curves". I've put a 
screenshot here: http://www.trektech.de/test/hobbitgraph.png
The thing seems to have started when I put the DNS keyword to my two DNS 
servers. Before it gave a nearly zero line.

I want to add about 400 network switches which should only do a ping test 
and I fear that this would extremely increase the runtime of the bbtest.
What can I do to decrease the runtime?

Thorsten Erdmann
ITI/EP68
Mercedes Benz Werk Hamburg
Tel.: +49-40-7920-2593

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