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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The problem (as I’m sure you know)
is that RRDTool will not allow you to store data for a time previous to its
last update timestamp. IE, you cant load this historical data into the archive
retroactively. Similarly, when you’d accidentally set the clock forward
and stored some incorrect data for a time in the future, and then set the clock
back correct again, rrdtool then refused to accept any more data until the last
used time had been reached (again).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The only way I can think of to fix this is
a bit long-winded.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>1) Get your *<b><span style='font-weight:
bold'>old</span></b>* rrd file. Use ‘rrdtool dump’ to dump it to
XML<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>2) Get your *<b><span style='font-weight:
bold'>new</span></b>* rrd file. Also dump this to XML.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>3) Write some code (perl?) that will
generate a new XML file by reading the OLD dump up until the specified time,
and then read the new file. Note that you will need to do this for all 4 RRAs.
Also, keep the *<b><span style='font-weight:bold'>new</span></b>* file data
for everything else (eg, current ds values).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>4) Use rrdtool to load the XML file and
generate a new .rrd file from it using ‘rrdtool restore’.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>5) Back up your existing .rrd file, and
swap in this newly created .rrd file.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>This does work (I’ve done it here
under different circumstances) but you need to be careful. Also, you need to
script it all to run automatically so it can finish within 5mins and thus you don’t
lose any incoming data while the process runs. Probably you’ll want to
test it out on a minor rrd file first before running it on the whole lot.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>You can use a similar method to erase
incorrect data, move data in time, or remove spikes. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Hope this helps, and hope you know enough
scripting to code it…<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Steve<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span lang=EN-US
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</span></font></b><font
size=2 face=Tahoma><span lang=EN-US style='font-size:10.0pt;font-family:Tahoma'>
mrtg-bounces@lists.oetiker.ch [mailto:mrtg-bounces@lists.oetiker.ch] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Charles V. Boehnlein<br>
<b><span style='font-weight:bold'>Sent:</span></b> Saturday, 28 April 2007
05:51<br>
<b><span style='font-weight:bold'>To:</span></b> mrtg@lists.oetiker.ch<br>
<b><span style='font-weight:bold'>Subject:</span></b> [mrtg] Timestamp problems
- lost data</span></font><span lang=EN-US><o:p></o:p></span></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>The server we use for MRTG recently had its system time changed to an
incorrect time.<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>After changing the system time back to the correct time we continued to
get a "timestamp" error message and the graphs would not display.<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>How can we fix this problem?<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>We had to recreate the RRD databases and lost our old history. We saved
those files but don't see a way to import that data back into the current RRD
databases.<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Sorry if this is a repeat request but I could not find a search feature
for the mailing list archives and a search on the MRTG web page did not return
any results for this problem.<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Thanks,<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Charles<o:p></o:p></span></font></p>
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