95th Percentile Help...

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DJEMiVT
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Joined: Fri Nov 14, 2003 2:44 pm

95th Percentile Help...

Post by DJEMiVT »

Hello, I have a couple of catalyst 5500 switches that do a bunch of vlans. Anyway, on some of the graphs the 95th percentile shows up correctly but on the high bandwidth graphs it won't show the red horizontal line. Any ideas? It seems to work great below 2megabits. However, I do have one graph where it's zoomed in to 1.5kilobits and it's missing the 95th also. How do I fix this?

Thanks, much appreciated, great program!

Emi.
DJEMiVT
Posts: 6
Joined: Fri Nov 14, 2003 2:44 pm

Ok...

Post by DJEMiVT »

Ok so I figured out why this isn't graphing the line, because in+out is off the top of the graph and the autoscale uses the bandwidth not the 95 line to scale the graph. Anyway, I think this is livable as long as the mbit in+out number in the border of the graph is actual 95%? can someone confirm this? Also, is there a way to base the 95 perecentile off of just the greater of inbound/outbound traffic rather than the sum of the two? Please let me know if this is possible.

Thanks!
raX
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Post by raX »

This is not currently possible with the latest version of Cacti. I do have some working code that does exactly this. I considered adding it to 0.8.4, but I wasn't sure if there would be any interest at this point. Considering that this is how 95th percentile *should* be calculated, I will probably make this the default for 0.8.5.

If you are really curious about this code, let me know and I might be able to work something out.

-Ian
eagle
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Joined: Thu Jan 15, 2004 1:44 pm

Post by eagle »

raX wrote:This is not currently possible with the latest version of Cacti. I do have some working code that does exactly this. I considered adding it to 0.8.4, but I wasn't sure if there would be any interest at this point. Considering that this is how 95th percentile *should* be calculated, I will probably make this the default for 0.8.5.

If you are really curious about this code, let me know and I might be able to work something out.

-Ian
Hi.

I'm wondering when this 'feature' will be available. For now, I've turned off auto scaling, but when the max values from the switch go spreading aroud, it would be nice to have the max on the scale auto-set.

If there is a code I could copy/paste, that's fine too, offcours. I'm also using cactistoric, if it should matter.
raX
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Post by raX »

This feature will be available when 0.8.5 is released, hopefully sometime next week if I get some testing done over the weekend.

If you want to try something now, feel free to try the rrd.php that is in CVS:

http://cvs.raxnet.net/cgi-bin/viewcvs.c ... text/plain

Using this feature is simple, just replace the "current" or "total" with "max" in your 95th percentile variable.

-Ian
Guest

Post by Guest »

raX wrote:Using this feature is simple, just replace the "current" or "total" with "max" in your 95th percentile variable.

-Ian
Hi Ian, thanks for your reply.

This is the first time I've dealt with rrd and graphs, so please excuse the question:

where do I substitute the current/total with max?

Btw, great tool!

Hans
raX
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Post by raX »

Anonymous wrote:where do I substitute the current/total with max?
When you go to edit the 95th percentile graph template, the last two items should contain a variable that looks like "|95:bits:0:total:2|". You simply need to edit these two items and change 'total' in the variable to 'max'. You also need to make sure "Traffic (traffic_in)" is selected for the data source in these two graph template items.

After making these two changes, edit the "Inbound Data Source" graph item input and add the last two items (10 and 11 in my case) to the input by checking them.

-Ian
sbraskett

95th Percentile - logic error?

Post by sbraskett »

Hello,
I'm running cacti-0.8.5a on Redhat 9 with cactistoric. No problems, no error messages, just some counter-intuitive results with one of my 95th percentile graphs.

Here is the graph in question:

Image

As you can see the 95th percentile HRULE is above the max traffic. I have tried changing the autoscale settings to no effect.

Thanks,
Scott
raX
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Post by raX »

It is possible to get a 95th percentile reading above the maximum if you use the "total" calculation type. This is because Cacti sums the inbound and outbound before making the calculation. Instead, the "max" type will probably provide you with a more acurate reading.

-Ian
sbraskett

95th Percentile Logic Error?

Post by sbraskett »

Actually I am using MAX. Here are the settings from the graph template:

Item # 10 HRULE: |95:bits:0:max:2| HRULE AVERAGE
Item # 11 COMMENT: (|95:bits:6:max:2| mbit in+out)

Is there somewhere else I need to make sure I have MAX? Should the consolidation function also be MAX? Currently it's AVERAGE, but changing it doesn't seem to help.

Thanks,
Scott
raX
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Re: 95th Percentile Logic Error?

Post by raX »

sbraskett wrote:Is there somewhere else I need to make sure I have MAX? Should the consolidation function also be MAX? Currently it's AVERAGE, but changing it doesn't seem to help.
These are the only two items you should have to check. The consolidation function should be set to AVERAGE as this field has no effect on the 95th percentile calculation. I noticed by your screenshot that you are using Cactistoric. I am not sure if Cactistoric takes the correct timespan into account when performing the 95th percentile calculation. The next release of Cacti which is due out shortly should take the complete timespan into account when displaying 95th percentile or bandwidth summation calculations.

-Ian
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