On Wed, Sep 17, 2008 at 14:15, Ofer Inbar <[EMAIL PROTECTED]> wrote: > This has happened to me at both places where I've used Ganglia, one > running 3.0.7 on RHEL 5 and the other running 3.1.0 on CentOS 4. > Occasionally, the graphs for a particular time range (like, say, day) > look blocky, as if there isn't enough resolution in the data. It's as > if they were being taken from the RRAs for the next-higher time range, > but I'm not sure that's what is actually happening.
Graphs are 100% generated by rrdtool; what version are you running? (not that I know of any problems with rrdtool, but it is relevant information). I have seen this sort of behavior, but it's because I was using an old timeframe. The URLs used for generating graphs include a start time and a range. When these URLs are created, the appropriate (i.e. highest resolution) RRA for that range is automatically used by rrdtool. If enough time passes, but the same URL is used, rrdtool may be forced to use a less precise RRA. For example, if you go poking around in graph.php, you'll eventually find that the --start and --end values passed to rrdtool are computed based the current time and the timerange (e.g. hour, day, week, month, year) indicated in the URL. So in effect, you get a sliding window at a fixed point in time. As that window gets farther into the past, rrdtool must use progressively less precise RRAs in order to display that time range. When you see this happen again, look for an "st=XXXXXXXX" value in the URL. That indicates the "source time" of the graph, which is used to calculate the start and end times used in the graph. I tend to think of it as an anchor in time for a given window. When you reload a page, new source times are determined, and the graphs should all look 'normal' again. -- Jesse Becker GPG Fingerprint -- BD00 7AA4 4483 AFCC 82D0 2720 0083 0931 9A2B 06A2 ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Ganglia-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ganglia-general
