remove troughs from rrd files (like killspike.sh, but for troughs

killtrough.sh

#!/bin/sh

#
# killtrough
# Remove (presumably erroneous) troughs from RRD files
#
# Matt Zimmerman <[email protected]>, 05/2002
#
# Modified by Andre Lewis to kill troughs instead of peaks 10/2012

set -e

usage() {
    >&2 echo "Usage: $0 <ds> <min> <rrd>..."
    >&2 echo
    >&2 echo "Remove all troughs below <min> from <ds> in the RRDs <rrd>..."
    exit $1
}

backupdir=backup.killspike2

ds=$1
min=$2

if [ -z "$ds" -o -z "$min" ]; then
    usage 1
fi

shift 2

rrds=$*

if [ "$ds" = "-h" -o -z "$rrds" ]; then
    usage 1
fi

mkdir $backupdir
echo "Making backups in $backupdir"

if type tempfile >/dev/null 2>&1; then
    tempfile=`tempfile`
else
    tempfile=killspike2.$$
fi

for rrd in $rrds; do
    echo $rrd

    oldmin=`rrdtool info "$rrd" | awk '$1 == "ds['$ds'].min" { print $3 }'`
    if [ -z "$oldmin" ]; then
        >&2 echo "Could not determine current min for DS '$ds' in $rrd"
        exit 1
    elif [ "$oldmin" = "NaN" ]; then
        oldmin=U
    fi

    cp "$rrd" "$backupdir"
    rrdtool tune "$rrd" --minimum "$ds:$min"
    rrdtool dump "$rrd" > "$tempfile"
    mv "$rrd" "old.$rrd"
    rrdtool restore -r "$tempfile" "$rrd"
    rrdtool tune "$rrd" --minimum "$ds:$oldmin"
done

rm -f "$tempfile"