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I found my RRD weirdness with illegal updates (2 in same time) - probable idea or fix required to resolve

2 messages in this thread

list Kent Brodie · Wed, 2 Aug 2006 12:49:36 -0500 · 
Hi everyone.   Some time ago, I asked about this:

 
2006-08-02 12:24:50 RRD error updating
/home/hobbit/data/rrd/taylor.brc.mcw.edu/disk,root.rrd from
141.106.224.178: illegal attempt to update using time 1154539490 when
last update time is 1154539490 (minimum one second step)

 
Nobody had anything useful for me, because there could be tons of
causes....   However, just now, I finally figured it out.

 
Seems that the previous sysadmin decided to create a home directory for
"root" to store all his files (tarballs, etc).   It was mounted as
simply, "/root".

 
This is all perfectly valid, *UNTIL* we get to rrd and disk usage.

 
Within the realm of hobbit and rrd, the actual root file system ("/") is
stored in rrd as /home/hobbit/data/rrd/taylor.brc.mcw.edu/disk,root.rrd 

 
When the client system had both "/" and "/root", this had the nifty side
effect of causing hobbit'd RRD environment to become confused--   that's
why I had an extra graph that had a placeholder, but nothing was being
generated!   That's because I had 17 mounted filesystems, which (divided
by 4) is 5 graphs.   But the 5th graph never showed up, and I looked
carefully and figured out it was "/root" that wasn't being graphed.
That's when the lightbulb went off.      Two file systems "/" and
"/root" were being called the same thing in terms of rrd:  "root".
Oooops.

 
SO..........        While I decided to simply move the "/root" crud to
somethere that made more sense...    I have apparently tripped upon
something that hobbit+rrd isn't prepared to deal with, which is a file
system called "/root".    While I think this would be rare, it's
possible.    Not sure how it would be handled?   Maybe call the "/" file
system "root~" or include some other special character in the name?


Kent C. Brodie - user-da7f7d5174c0@xymon.invalid

Department of Physiology

Medical College of Wisconsin

(XXX) XXX-XXXX
list Henrik Størner · Tue, 8 Aug 2006 23:05:50 +0200 ·
▸ quoted from Kent Brodie
On Wed, Aug 02, 2006 at 12:49:36PM -0500, Brodie, Kent wrote:
When the client system had both "/" and "/root", this had the nifty side

effect of causing hobbit'd RRD environment to become confused [snip]
▸ quoted from Kent Brodie
Two file systems "/" and "/root" were being called the same thing in 
terms of rrd:  "root". Oooops.

SO..........        While I decided to simply move the "/root" crud to
somethere that made more sense...    I have apparently tripped upon
something that hobbit+rrd isn't prepared to deal with, which is a file
system called "/root".    While I think this would be rare, it's
possible.    Not sure how it would be handled?   Maybe call the "/" file
system "root~" or include some other special character in the name?
You're right that Hobbit didn't anticipate this setup. The disk-RRD
naming was adopted from LARRD which uses this scheme; Hobbit just 
kept it to maintain compatibility and because I didn't expect it 
to cause any problems.

I think this is sufficiently rare that it's not really worth the
effort to arrange for some special-case handling of a "/root"
filesystem. So - at least for now - I'll leave it as-is.


Regards,
Henrik