[rrd-users] RRD suddenly empty

Alex van den Bogaerdt alex at ergens.op.het.net
Fri Jan 4 15:53:04 CET 2008

On Fri, Jan 04, 2008 at 03:31:49PM +0100, Sandro Roth wrote:
> Thanks for your reply!
> Of course the graph isn't empty anymore and is currently showing correct
> values again..
> But I'll keep your advise in mind when it behaves like this again.. And I
> also redirected the output to a logfile, just in case :)

Make sure those contain a timestamp instead of "N".  If not, you
loose information, e.g. when your computer's clock is set wrong.
In case of trouble, look at timestamps and at update values.

Regularly backup your .rrd file and your .updates file.

In case of trouble, you can restore the .rrd file and replay every
update after checking for and correcting errors.  Use rrdtool last
to find out when your restored database was last updated, then rerun
every update command thereafter.

And of course don't forget you need to prune your .updates file, or
else it will become too big after a while.  I have a couple of cron
jobs for that purpose. One of them renames the file to a name including
datetime, the other removes all files but the last ten.

Alex van den Bogaerdt

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