[rrd-users] Re: DST beginner question

Tue Nov 7 21:23:38 MET 2006

Hi,

it is good to know that I can do the calulations (to byte or bit) later 
by building the graph, because than I have more possibilities for the 
graph (only the web script must written for that - should be no problem. 
Thanks for that idea.

Hoever, I do not really understand how the rrdtool creates some values.

I have checked the following:

-bash-3.00$ /usr/local/rrdtool-1.0.49/bin/rrdtool create 
/data/www/htdocs/rrd/atm/atm_vcc_cell-to-bit/test.rrd --start 1162910692 
--step 900 DS:input:ABSOLUTE:900:U:U RRA:AVERAGE:0.5:1:8640

-bash-3.00$ /usr/local/rrdtool-1.0.49/bin/rrdtool info 
/data/www/htdocs/rrd/atm/atm_vcc_cell-to-bit/test.rrd
filename = "/data/www/htdocs/rrd/atm/atm_vcc_cell-to-bit/test.rrd"
rrd_version = "0001"
step = 900
last_update = 1162910692
ds[input].type = "ABSOLUTE"
ds[input].minimal_heartbeat = 900
ds[input].min = NaN
ds[input].max = NaN
ds[input].last_ds = "UNKN"
ds[input].value = 0.0000000000e+00
ds[input].unknown_sec = 892
rra[0].cf = "AVERAGE"
rra[0].rows = 8640
rra[0].pdp_per_row = 1
rra[0].xff = 5.0000000000e-01
rra[0].cdp_prep[0].value = NaN
rra[0].cdp_prep[0].unknown_datapoints = 0

I bring the following data/values into the rrd database:

Date        Time        unixtime    diff    input
07.11.2006    15:46:32    1162910792        7542433
07.11.2006    16:02:02    1162911722    930    6517020
(07.11.2006    16:16:47    1162912607    885    6258907)
(07.11.2006    16:31:49    1162913509    902    11748027)
(07.11.2006    16:46:49    1162914409    900    14060652)
(07.11.2006    17:01:56    1162915316    907    13571731)

-bash-3.00$ /usr/local/rrdtool-1.0.49/bin/rrdtool update 
/data/www/htdocs/rrd/atm/atm_vcc_cell-to-bit/test.rrd 1162910792:7542433

-bash-3.00$ /usr/local/rrdtool-1.0.49/bin/rrdtool info 
/data/www/htdocs/rrd/atm/atm_vcc_cell-to-bit/test.rrd
filename = "/data/www/htdocs/rrd/atm/atm_vcc_cell-to-bit/test.rrd"
rrd_version = "0001"
step = 900
last_update = 1162910792
ds[input].type = "ABSOLUTE"
ds[input].minimal_heartbeat = 900
ds[input].min = NaN
ds[input].max = NaN
ds[input].last_ds = "UNKN"
ds[input].value = 6.9390383600e+06
ds[input].unknown_sec = 0
rra[0].cf = "AVERAGE"
rra[0].rows = 8640
rra[0].pdp_per_row = 1
rra[0].xff = 5.0000000000e-01
rra[0].cdp_prep[0].value = NaN
rra[0].cdp_prep[0].unknown_datapoints = 0

-bash-3.00$ /usr/local/rrdtool-1.0.49/bin/rrdtool update 
/data/www/htdocs/rrd/atm/atm_vcc_cell-to-bit/test.rrd 1162911722:6517020

-bash-3.00$ /usr/local/rrdtool-1.0.49/bin/rrdtool info 
/data/www/htdocs/rrd/atm/atm_vcc_cell-to-bit/test.rrd
filename = "/data/www/htdocs/rrd/atm/atm_vcc_cell-to-bit/test.rrd"
rrd_version = "0001"
step = 900
last_update = 1162911722
ds[input].type = "ABSOLUTE"
ds[input].minimal_heartbeat = 900
ds[input].min = NaN
ds[input].max = NaN
ds[input].last_ds = "UNKN"
ds[input].value = 0.0000000000e+00
ds[input].unknown_sec = 122
rra[0].cf = "AVERAGE"
rra[0].rows = 8640
rra[0].pdp_per_row = 1
rra[0].xff = 5.0000000000e-01
rra[0].cdp_prep[0].value = NaN
rra[0].cdp_prep[0].unknown_datapoints = 0

How does the rrdtool work? The resulting values are not really correct ?!?!
I can not see the last input value!!!

ds[input].last_ds = "UNKN"    Why is it UNKOWN?
ds[input].value = 0.0000000000e+00    Why is it 0?
ds[input].unknown_sec = 122    Why is it 122 and not 30 (930-900[step])?

br
Christoph

Alex van den Bogaerdt wrote:
> On Tue, Nov 07, 2006 at 07:14:18PM +0100, Christoph Schwabl wrote:
>
>   
>> 1. file 07.11.2006,15:46:32,7542433,Ingress Cells (ATM)
>> 2. file: 07.11.2006,16:02:02,6517020,Ingress Cells (ATM)
>> 3: file: 07.11.2006,16:16:47,6258907,Ingress Cells (ATM)
>> 4: file: 07.11.2006,16:31:49,11748027,Ingress Cells (ATM)
>> 5: file: 07.11.2006,16:46:49,14060652,Ingress Cells (ATM)
>> 6: file: 07.11.2006,17:01:56,13571731,Ingress Cells (ATM)
>> ... (I get all 15 minutes a new file.)
>>
>> That means:
>> The system has collected between 15:46:32 and 16:02:02 exactly 6517020 
>> ingress atm cells.
>> Between 16:02:02 and 16:16:47 exactly 6258907 ingress atm cells.
>> and so on.
>>     
>
> So, in roughly 15 minutes, the amount of cells is received.
> In other words, this is like a counter that's reset every
> time it is read --> ABSOLUTE.  You don't have to reset this
> counter, the device seems to do this for you.
>
> The result is 6517020 ingress atm cells in (16:02:02 - 15:46:32),
> which is 15 minutes 30 seconds --> 7007.5 cells per second. This
> is the computed rate, before normalization occurs.
>
>   
>>>> I want to build a graph in bits/s.
>>>>         
>
> Once you have the proper rate of cells per second, it is easy,
> using CDEF, to multiply by <bytes per cell> and by <bits per byte>.
>
> Can you manage from here?
>
>   

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