Cheshire Cat Computing

Hi Steve

You were looking for input on the mouseover time/date feature. i think it is fantastic. The only thing that is wrong with it is that it is exactly 1 hour off. i am not sure if that is a configuration error on my part but the time on the bottom of the graph is correct. You said it wouldn't work on user defined graphs but is seemed fine for me.

Sounds like you have one of the 2.18beta versions, where mousover now works on userdefineds. If you have the latest beta, then you can even get the data values in the mousover popup (you need to enable it in the routers2.conf though first).

If the time is out by 1hour then its a timezone issue. Unfortunately, there are timezones defined in your browser, on the MRTG server, and for the monitored device - the RRD works using UTC so it doesn't care, but for the time popup, all of these must be configured correctly. The code tries to adjust for things like the local timezone of the browser, which may be different from the timezone of the MRTG server and the timezone of the monitored device.

Check the timezone settings on all these things are right. You can force a timezone setting in the routers2.conf as well, though this is a last ditch effort. Also, Windows servers tend to be worse at this due to their lesser support for timezones in the compiled RRD.so and Perl libraries. Install the Time::Zone (perl module) if you can, this often helps.

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Steve Shipway
UNIX Systems, ITSS, University of Auckland, NZ
Woe unto them that rise up early in the morning... -- Isaiah 5:11

All I did to fix the hour offset was to comment out the timeszone section and it worked like a charm.i didn't see where to enable the mouseover popup in the conf file.

I got the data portion to work as well.

Awesome feature!

_________________
Steve Shipway
UNIX Systems, ITSS, University of Auckland, NZ
Woe unto them that rise up early in the morning... -- Isaiah 5:11

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--
Garry Cook

The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing.
~Albert Einstein

The time in the x-axis is calculated by the rrdtool library, from the actual data point and the timezone settings (symbolically) passed to the library. The time in the popup, on the other hand, is calculated by the javascript on your local browser based on the number of pixels offset from the image righthand side and the end time (UCT) of the graph, and the timezone of your local browser, and the timezone passed (numerically) from the web server. This causes any number of problems.

There can be inconsistencies between the timezone libraries used by perl (to obtain timezone offset) and RRDTool (for the graph). Sometime these can be helped by installing the Time::Zone package which is more detailed and supports symbolic timezones. Also, although the code attempts to cancel out the effect of your browser's timezone and clock, this seems to be able to affect things still (may be a browser-specific issue).

It may be that the off-by-one is a DST issue whereby one of the timezone functions is calculating the time correctly, and the other is missing/adding DST. I haven't managed to duplicate it here yet since the initial chaos (New Zealand has a timezone of +12/+13 and the +13 confused things considerably at one point).

_________________
Steve Shipway
UNIX Systems, ITSS, University of Auckland, NZ
Woe unto them that rise up early in the morning... -- Isaiah 5:11

Hmmm... I see. Well, I do have Time::Zone installed, and it still occurs.
Actually, in looking at it more closely today, this appears to be a very different issue than I at first thought.

At 2 AM on the graph, the pop-up displays 00:00. So, it would appear as though the pop-up is actually two hours behind. However, when I slide over to 4 AM, the pop up displays 00:25. At 6 AM, the pop-up shows 00:49.

It appears to me as if the pop-up is actually calculating about 12 minutes each hour. Is this due to the fact that it is basing calculations on 5 minute polling intervals, when I'm actually polling every minute?

Update: My graphs are again showing pop-up times exactly one hour behind the actual time. I know I'm not crazy, and the description above is what I saw a few hours ago, but I just spent the last 10 minutes trying to reproduce it and I cannot.

_________________
--
Garry Cook

The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing.
~Albert Einstein