[rrd-users] rrd graph not flushing cached data (symlink problem)

[Eduardo Bragatto]

Hi,

I have continued researching this problem and after running strace on  
the rrd graphs calls, I found the issue is being caused by a symlink  
in the path.

Here's what I see in the telnet,  when testing:
with symlink:
FLUSH /usr/local/rrd/myproject/repository/local/switches/myswitch/ 
10146.rrd
0 Nothing to flush: /usr/local/rrd/myproject/repository/local/switches/ 
myswitch/10146.rrd.

without it (same file):

Flush /usr/local/rrd/myproject/rrd/switches/myswitch/10146.rrd
0 Successfully flushed /usr/local/rrd/myproject/rrd/switches/myswitch/ 
10146.rrd.

According to the documentation, symlinks are not allowed in the base  
directory:

"WARNING: The paths up to and including the base directory MUST NOT BE  
symbolic links. In other words, if the base directory is specified as:

     -b /base/dir/somewhere
... then NONE of the following should be symbolic links:

     /base
     /base/dir
     /base/dir/somewhere"

Since I'm not using -b, it's configured to default /tmp. My rrd files  
are stored in a long path, like this:
/usr/local/rrd/myproject/rrd/switches/port.rrd
However, I'm referencing the files via a symlink:
/usr/local/rrd/myproject/repository/local/switches/port.rrd
Where:
/usr/local/rrd/myproject/reporsitory/local is a symlink to /usr/local/ 
rrd/myproject/rrd

Considering that there's no symlink in the base directory (where the  
documentation says it's forbidden) and also that I'm using an absolute  
path, outside the base directory, shouldn't the symlink work in my case?
According to the documentation I'm not doing anything wrong, but the  
software does not work as expected. Do we have a bug in rrdcached, or  
is it the documentation that's not complete on how it deals with  
symlinks?

Thanks,
Eduardo Bragatto.
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