[smokeping-users] Re: bandwidth hack. {Tarandi}

[Ali ISIK]

The issue is that our update interval is set to one minute,
because our operators want that resolution.  we run under
mod-perl.

I have mrtg plotting the server load, memory use etc
on the smokeping servers.  I see now that since I made
the changes last night, the load went from and average
of 120% down to 65%, but I would rather observe
the load graphs for at least a week before I make a
judgement about the effectiveness of the change.

I also spoke with two operators now and they seem
to be happy that the pages seem to be loading faster
and they say they do not mind having to click one more
link to reach the other intervals than the smallest, which
is almost always what they want to check.

I emphasize, though, the heavy load is only due to the
fact that our operators typically have at least 20 detail
pages open each (for the most important routes /
customers) and refreshing every minute.  That adds
up to more than 500 large png files (out of a total pool
of many thousands of smokeping png files) *created* every
minute
(
because:
    o    they are requested with at least that frequency
    o    the smokeping resolution is 60 seconds, not the
         default 300 seconds
    o    each detail page contains 7 graphs, not the default 4
)
and most of these pages are *served* several times a
minute (because there are several operators working
independently of each other).  An analysis of server
load showed that this was the main cause.

Simpler solutions would be to

    o    Ask operators to check the overview pages only
    o    Ask operators not to have all the pages open and
         refreshing constantly, but one-at-a-time

But these decisions I leave to them.  They want to keep
an eye on packet loss and jitter distribution, but the
overview page does not provide those.  They also want
to keep all the pages open so they can keep scanning them
in fast serial fashion.

cheers,

--ali


----- Original Message ----- 
From: "Tobias Oetiker" <oetiker at ee.ethz.ch>
To: "Ali ISIK" <ali at esertelekom.com>
Cc: <smokeping-users at list.ee.ethz.ch>
Sent: Thursday, May 06, 2004 9:02 AM
Subject: Re: [smokeping-users] bandwidth hack. {Tarandi}


Hi Ali,

if done right, your customers should not be redownloading the
longer term files because they do not change as frequently than the
short term ones ... smokeping also does not regenerate these files
except when they are out of date ... what it does at the moment is
looking at the file to figure if it needs updating ... because the
cgi runs under speedy (yours does, right ?) you could add a
persistent variables (use vars) to keep track of when the png was
last updated and only have the rrdtool code look at it every 5
minutes or so ...

cheers
tobi

Today Ali ISIK wrote:

> Our smokeping installation monitors hundreds of endpoints
> with a one-minute detail.  We have several operators in multiple
> cities constantly refreshing almost all detail pages, which are
> configured to have 7 big png files each.  What the operators are
> usually interested in is the top graph.  To reduce the burden on
> the Feathered One, I just put in the following hack into the .pm
> file.  It seems to work, but I need to see the changes in server
> load and user sentiment over the next few days to really judge
> its effect.  For the moment I am pretty optimistic.  What do you
> guys think?  cheers.
>
> --ali90
>
> ----------------BEGIN snippet----------------------
> ### META: BEGIN RAI bandwidth hack
>         $q->param('detail')
>             or do{
>                 $page .= sprintf qq|<P><A HREF="%s&detail=yes">Graphs for
> larger intervals</A><BR><I>( Please use only as needed -- RAI )</I></P>|,
> $q->self_url();
>                 last;
>             };
> ### META: END RAI bandwidth hack
>       }
>     return $page;
> }
>
> sub display_webpage($$){
>     my $cfg = shift;
>     my $q = shift;
>     my $open = [split /\./,( $q->param('target') || '')];
>     my $tree = $cfg->{Targets};
>  ----------------END snippet----------------------
>
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