Munin/rrdtool spike removal

Occasionally I see spikes on my network card charts. I found this article which says how to remove them and basically it shows how to convert the rrd file to xml and vice versa, so it's worth remembering.

cd /var/lib/munin/HOSTNAME

# To export rrd file to xml, use
rrdtool dump file.rrd > file.rrd.xml

# Move the rrd file to backup
mv file.rrd file.rrd.bak

# To convert from xml to rrd, use:
rrdtool restore -r file.rrd.xml file.rrd

# In case running under different user (e.g. root), don't forget to change back the ownership of rrd files:
chown munin:munin file.rrd

# To regenerate graphs, run as munin:
/usr/share/munin/munin-graph --nolazy --host $HOSTNAME --force

mycal2rem

I was using ical2rem.pl to pull data off my Google calendar and display it in wyrd, which I'm using on my laptop. After a while I found a few shortcomings:
- the parsing of the .ics file from Google took about 25 seconds (on my Intel CoreII Duo T7100) during which the CPU was fully utilized
- the script does not use the features of remind format, e.g. the repeating events are created as multiple entries in the remind file

The mycal2rem.pl is far from full implementation of the .ics format (RFC 5545), but currently it parses all events from my calendar just fine.

The script can be found at github.