[rrd-users] Graphing potentially missing files
linux at thehobsons.co.uk
Fri Dec 3 13:09:08 CET 2010
Steve Shipway wrote:
>When you run rrdgraph in rrdcached mode (either via the environment
>variable, or using the --daemon option) then it flushes the cache
>data and also accesses the data over the rrdcached connection. It
>doesnt use the local file.
>RRdtool in rrdcached mode will use the local file only if (a) you're
>asking for a function not supported by the rrdcached, AND (b) you're
>using UNIX sockets (since if using TCP sockets, the rrd file is not
>on this server), AND (c) it can read/write the file (since you may
>have given permissions to allow the file to only be accessed by the
>rrdcached). If using the trunk 1.4 version, then this means that
>the supported functions are update, first, last, create (with
>limitations), fetch, graph and info.
I'm using 1.4.3 from Debian Lenny-backports.
After a little experimentation, I see I have to specify the correct
local file path - if I link from one directory into the rrdcached db
directory then it's not recognised.
Just to complicate matters, when I get down to modifying my scripts,
I now remember that most of my graphs are built with rrdcgi - because
of the difficulty of building a huge parameter list and the lack of a
"read the rest from stdin" option to rrdgraph. Unless you now tell me
that there is such an option and I've missed it !
>You can ask rrdcached to flush caches using 'rrdtool flushcached'
That's handy since rrdcgi doesn't seem to have been updated to
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