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Hi Jimmy;<br>
<br>
1) Granularity is simply the level of detail at which data is recorded
in the RRD file -- do we record every data point (steps = 1), or
aggregate multiple data points into a single value (steps > 1)?
AFAIK, there is no performance penalty either way; it's simply a matter
of balancing history, presentation and disk space.<br>
<br>
2) Smokeping (and all RRD-based applications) use ALL of them. Data
is recorded at both steps=144 and steps=12. The difference comes when
you draw graphs -- rrdtool will use the lowest granularity it can to
draw graphs, given time constraints (that is, if you tried to draw a
graph showing 20 days of history, you wouldn't have enough data at
steps=12, so it would use the steps=144 data instead).<br>
<br>
3) Keep in mind that step=300 would affect Smokeping's poll rate as
well, not just the database storage. But yes, you can play with any
(or all) of step, steps, and rows to retain data as long as you want.<br>
<br>
Typically what I do when deploying Smokeping is sit down and figure out
a few things:<br>
- How often do I need to poll (the step setting)<br>
- How much history do I need?<br>
- How wide (in pixels) will my graphs be? (the 'width' settings in
*** Presentation ***)<br>
- What time ranges will I be graphing (e.g. 6 hours, 24 hours, 7
days, 30 days, 365 days, etc)<br>
<br>
Using all that information, I'll do some quick math to figure out the
steps and rows settings I need to make the graphs look nice -- that is,
to use consistent and easy-to-see-sized bars (1 pixel wide bars are
hard to see -- 4-8 pixels are much easier!).<br>
<br>
- Peter<br>
<br>
<br>
<br>
Jimmyboy wrote:
<blockquote
cite="mid:c98caf811001040647w7206b111r9c4efda90d0fe877@mail.gmail.com"
type="cite">
<div> </div>
<div>Thanks Peter, for the detailed description. However, I have some
doubts.<br>
<br>
1. What does granularity mean here? How does a lower or a greater
granularity affect or improve the performance of Smokeping’s graphing?
In other words, how does that bother an administrator?<br>
<br>
2. With steps=144, granularity is 72 minutes lasting for 36 days,
with steps=12, granularity is 6 minutes lasting for 18 days. Which one
does Smokeping use or default to?<br>
</div>
<div>3. With this calculation, does it mean that <strong>“step=300”</strong>
under my <strong>*** Database ***</strong> section in <strong>config </strong>file
will always maintain a graph of <strong>360 days</strong>? If yes, can
I simply change the value of <strong>step</strong>, <strong>steps</strong>
or <strong>rows</strong> to retain data for as long as I wish to?<br>
<br>
Regards,<br>
Jimmy</div>
<div> </div>
<div>=-=-=-=</div>
<div><br>
<br>
</div>
<div class="gmail_quote">On Sat, Jan 2, 2010 at 12:27 AM, Peter
Kristolaitis <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:alter3d@alter3d.ca">alter3d@alter3d.ca</a>></span>
wrote:<br>
<blockquote
style="border-left: 1px solid rgb(204, 204, 204); margin: 0px 0px 0px 0.8ex; padding-left: 1ex;"
class="gmail_quote">
<div bgcolor="#ffffff" text="#000000">First of all, happy new year
to everyone on the list! I hope that 2010 is a productive and fruitful
year for you all.<br>
<br>
To answer the easy question first -- yes, your RRA files will be 2.8MB
forever. An RRA 'database' contains a finite, static number of
records, and old records are discarded as new data is put in; rrdtool
makes the files large enough to handle all possible records at creation
time, so your file will never grow.<br>
<br>
With regard to how long Smokeping will continue graphing -- well,
forever. Because old records are cycled out when new data is put in,
Smokeping will continue to operate indefinitely and will only show
'current' data. A related issue is how much *history* will be
retained, and this is strictly dependent on how you've configured
Smokeping (specifically, the 'step' value and the 'steps' and 'rows'
data from the RRA definitions in the '*** Database ***' section of the
configuration file).<br>
<br>
Example:<br>
<pre>*** Database ***</pre>
<pre>step = 30
pings = 20</pre>
<pre><pre># cons xff steps rows
AVERAGE 0.5 1 1008
AVERAGE 0.5 12 4320
MIN 0.5 12 4320
MAX 0.5 12 4320
AVERAGE 0.5 144 720
MAX 0.5 144 720
MIN 0.5 144 720
</pre></pre>
The 'step = 30' part means that Smokeping will poll (and thus generate
a new RRA row) every 30 seconds.<br>
<br>
The 'steps' part of the RRA definition are how many 'step's are
consolidated for a given row. In the example, we have 1, 12, and 144;
this means that we're storing data at 3 different levels of
granularity: 1*30 = 30 seconds, 12*30 = 360 seconds, and 144*30 = 4320
seconds.<br>
<br>
The 'rows' part of the RRA definition tells you how many records that
RRA definition will hold.<br>
<br>
Using 'step', 'steps' and 'rows', you can calculate how much 'time' an
RRA will cover:<br>
time in seconds = step * steps * rows<br>
<br>
So if we look at the line "AVERAGE 0.5 144 720", it will hold:<br>
time = 30 * 144 * 720 = 3,110,400 seconds (36 days)<br>
<br>
This means that you will be able to get at most 36 days of history at a
granularity of 72 minutes (30*144 seconds). If you wanted to see the
data more granularly (6 minutes -- 30*12 seconds), then you would have
to set your graphs to show at most 30*12*4320 = 1,555,200 seconds (18
days).<br>
<br>
- Peter<br>
<br>
<br>
<br>
Jimmyboy wrote:
<blockquote type="cite">
<div>
<div class="h5">
<div>Hi All,</div>
<div> </div>
<div>I am using Smokeping 2.3 on my Ubuntu desktop machine since
more than 1 month. The size of all .rra files shows up as 2.8MB ever
since they have been created.</div>
<div> </div>
<div>Can anyone tell me how do I know till what time would
Smokeping continue graphing. Is it going to be a few months, 1 year or
2, etc...? Will the size remain 2.8MB forever?</div>
<div> </div>
<div> </div>
<div>Thanks,</div>
<div>Jimmy Jose</div>
<div> </div>
<div>=-=-=</div>
</div>
</div>
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</blockquote>
<br>
</div>
</blockquote>
</div>
<br>
</blockquote>
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