[collectd] Additonal mode: log

[Christophe Kalt]

On Apr 14, Sebastian Harl wrote:
| > i can argue this both ways.. CSV is more generic, but with
| > colons you have something that can easily be fed to rrdtool.
| 
| I'm just curious: Why would you want to use the log mode if you want to have
| the data in rrds?

Better control of how i create/update the rrd files, and
simpler to centralize the data on a single server.  I could
probably create the RRD files directly, but for this, i'd need
the RRAs to be configurable.

Also, it's less CPU intensive to call rrdupdate with x updates
than it is to call it x times for one update.