Data breaks due to server outage

[Amal]

Hi All:

I am just trying to monitor some remote hosts across wan and I assume if the WAN is down those data points are missed and the graph will show a break, since the remote server is running fine is there anyway to get back the missed data when the cacti server reestablishes communication with the monitored host.

Or is there a way I can configure cacti to query the sar output from the monitored hosts and graph them instead of using snmp, this way we know for sure we can get the old values also.

Any help is highly appreciated.

Thanks
Amal

[BSOD2600]

As for making your own script, I suggest you search the script forum first. If you can't find what you're looking for, then look into how to make your own: http://forums.cacti.net/viewtopic.php?t=11288

[gandalf]

When doing this, don't forget to remember that rrdtool does NEVER go back in time. If you made an update with timestamp x, there's no way to make another with y < x!
Reinhard

[Amal]

Thanks for the reply, the howto looks straight forward, but will cacti update multiple data points in single polling, lets say i have data for a particular device available to cacti with 5 data points at 5 min interval will cacti load all the 5 data points into rrd or will take only the latest, I mean will cacti read the 5th, 10th, 15th, .... minute value in a single polling if the data is available.

[gandalf]

No, cacti won't do that for you. The timestamp cacti uses is derived from the point in time the poller runs. But you may feed this into rrdtool externally. To do so, you may get the rrd file name from the Data Source. And then, you may write some script (e.g. perl) to feed the data using _your_ time stamp. So cacti will only be used as a graph management frontend, not as a data gatherer.
Reinhard