jmp242
2012-03-16 12:30:53 UTC
jmp242 [http://community.zenoss.org/people/jmp242] created the discussion
"Re: Custom command - inaccurate values being shown"
To view the discussion, visit: http://community.zenoss.org/message/65261#65261
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You're being bitten by RRDs. Basically, the RRDs always normalize data over time, and the resolution gets less over time also. I.e. by default you'll have a datapoint every 5 minutes. That gets less detailed - it throws out data - after 50 hours if I recall correctly. So if you look back a week later, you'll no longer have every 5 minutes a datapoint, you'll have every hour a datapoint, so the averaged numbers change.
Also when you zoom in, you're not zooming in like you expect. You're re-generating the graph for a different range of time, so again, the details change and the averages change. It gets more complicated, but read the rrd website and search these forums on RRD stuff and you'll find MANY discussions on the oddities.
--
James Pulver
ZCA Member
LEPP Computer Group
Cornell University
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"Re: Custom command - inaccurate values being shown"
To view the discussion, visit: http://community.zenoss.org/message/65261#65261
--------------------------------------------------------------
You're being bitten by RRDs. Basically, the RRDs always normalize data over time, and the resolution gets less over time also. I.e. by default you'll have a datapoint every 5 minutes. That gets less detailed - it throws out data - after 50 hours if I recall correctly. So if you look back a week later, you'll no longer have every 5 minutes a datapoint, you'll have every hour a datapoint, so the averaged numbers change.
Also when you zoom in, you're not zooming in like you expect. You're re-generating the graph for a different range of time, so again, the details change and the averages change. It gets more complicated, but read the rrd website and search these forums on RRD stuff and you'll find MANY discussions on the oddities.
--
James Pulver
ZCA Member
LEPP Computer Group
Cornell University
--------------------------------------------------------------
Reply to this message by replying to this email -or- go to the discussion on Zenoss Community
[http://community.zenoss.org/message/65261#65261]
Start a new discussion in zenoss-users by email
[discussions-community-forums-zenoss--***@community.zenoss.org] -or- at Zenoss Community
[http://community.zenoss.org/choose-container!input.jspa?contentType=1&containerType=14&container=2003]