create_cache_by_ratio.sh

#!/bin/bash

# cache construct variables
CACHE_DEV="/dev/sdb"
#SOURCE_DEV="/dev/sdd"
SOURCE_DEV="/dev/sdc"
CACHE_NAME="test-dmc"
# cache device whole size(byte)
CACHE_DEV_SZ=$(blockdev --getsize64 ${CACHE_DEV})
SOURCE_DEV_SZ=$(blockdev --getsize64 ${SOURCE_DEV})
# often 4K
BLK_SIZE=$(blockdev --getbsz ${CACHE_DEV})

MNT_DEST="/vmImages_iscsi/stg/129.201.00"

if [ -z $1 ] ;
then
    echo "usage $0 [ratio] [wb: -w]"
    exit
fi

if [ -z $2 ] ;
then
    echo "Write-through mode"
else
    echo "Write-back mode"
fi

ratio=$1
# capacity(blocks)
# ratio by source device
CACHE_CAP=$(echo "scale=0; (${SOURCE_DEV_SZ} * ${ratio}/100)/ ${BLK_SIZE}" | bc -l)

echo "Ratio : ${ratio}% : ${CACHE_CAP}/${CACHE_DEV_SZ}"

# dm-cache setup
# write-back
./dmc-setup.pl -o ${SOURCE_DEV} -c ${CACHE_DEV} -n ${CACHE_NAME} -s ${CACHE_CAP} $2

#mount cache device
mount /dev/mapper/${CACHE_NAME} ${MNT_DEST}
sleep 1

dmsetup table ${CACHE_NAME}
echo
dmsetup status ${CACHE_NAME}