I found my RRD weirdness with illegal updates (2 in same time) - probable idea or fix required to resolve
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 - brodie at phys.mcw.edu
Department of Physiology
Medical College of Wisconsin
(414) 456-8590
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] 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
participants (2)
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brodie@mcw.edu
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henrik@hswn.dk