[rrd-users] Question about rrdcached

Steve Shipway s.shipway at auckland.ac.nz
Tue Sep 25 06:27:03 CEST 2012

The order of the parameters to rrdcached are important.  Many apply only to the interface definitions following them.  So, your -b option (define base directory) should come before the -l (define listen port) option:

rrdcached -w 600 -z 10 -j /dados/rrd/cached/ -p /dados/rrd/rrdcached.pid -b /dados/rrd -l 

The reason for this is security -- you can define multiple listen ports with different levels of security and permissions.

The default behaviour on a TCP socket is -B -- disallow absolute ports and everything must be relative to the -b basedir.  Again, this is for security.

So, with the -l option at the end,  the basedir should take effect rather than the cwd where you started the rrdcached, and so this should work:

rrdtool fetch --daemon MAX -s  $(date --date "Aug
01 00:00:00 2012" +%s) -e $(date --date "Aug 08 00:00:00 2012" +%s)

assuming the rrd file exists on the rrdcached server, of course.

Steve Shipway
University of Auckland ITS
UNIX Systems Design Lead
s.shipway at auckland.ac.nz
Ph: +64 9 373 7599 ext 86487

From: rrd-users-bounces+s.shipway=auckland.ac.nz at lists.oetiker.ch [rrd-users-bounces+s.shipway=auckland.ac.nz at lists.oetiker.ch] on behalf of Jairo Gubler [jairo.gubler at digitro.com.br]
Sent: Saturday, 22 September 2012 5:16 a.m.
To: rrd-users at lists.oetiker.ch
Subject: [rrd-users] Question about rrdcached

Mustn't rrdtool connect to a remote host, through rrdcached? Was there
something wrong in my test below?

First I ran rrdcached:
rrdcached -l -w 600 -z 10 -j /dados/rrd/cached/ -p
/dados/rrd/rrdcached.pid -b /dados/rrd/

When I tryed to use '"rrdtool fetch" (from a remote machine or local
machine through TCP) I got some errors:

rrdtool fetch --daemon MAX -s  $(date --date "Aug
01 00:00:00 2012" +%s) -e $(date --date "Aug 08 00:00:00 2012" +%s)
ERROR: opening '': No such
file or directory

rrdtool fetch --daemon
/dados/rrd/ MAX -s $(date
--date "Aug 01 00:00:00 2012" +%s) -e $(date --date "Aug 08 00:00:00
2012" +%s)
ERROR: absolute path names not allowed when talking to a remote daemon

Without rrdcached:
rrdtool fetch /dados/rrd/
MAX -s $(date --date "Aug 01 00:00:00 2012" +%s) -e $(date --date "Aug
08 00:00:00 2012" +%s) | head
1343790300: 9.0000000000e+00
1343790600: 9.0000000000e+00
1343790900: 9.0000000000e+00
1343791200: 9.0000000000e+00
1343791500: 9.0000000000e+00
1343791800: 9.0000000000e+00
1343792100: 9.0000000000e+00
1343792400: 9.0000000000e+00

RRDCacheD 1.4.7
RRDtool 1.4.7

CentOS 5.8 32bits

Jairo Gubler

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