[rrd-developers] Ubuntu Lenny: rrd does not update the ctime and mtime of rrd-files

Kristoff Bonne kristoff.bonne at skypro.be
Tue Sep 28 13:49:45 CEST 2010

Hi Tobias,

Op 27-09-10 16:18, Tobias Oetiker schreef:
>> Now, we have a very strange fenomina:
>> mrtg does update the rrd-files as normal, but does not update the ctime
>> and mtime of the files.

> the reason for this behaviour is that rrtool uses memory mapped io
> for updating files ... some older linux kernels neglect to update
> the timesamps of the files thus edited ..
> rrdtool tool checks for this problem at compilation time and
> compensates by doing touch on the problem files ...

Hi, I've compiled the source from the debian repostitory.

After doing some testing (and setting up the path and ld_library_path to 
get it to load the correct binaries and libraries), we have found that 
the problem is still there.

Remember, we are using "mrtg".

I have done a "strace" of the mrtg-session, and I per file, I see a 
twice a "stat" and then twice an "open".

If I check with the default mrtg binaries, that's exactly the same.

Could it be that the problem is that you have build in this fix in 
"rrdtool" and not the rrd-libraties, but -as mrtg- uses the libraries 
directly the correcting "touch" is not done?

Cheerio! Kr. Bonne.

More information about the rrd-developers mailing list