Compacts VMDK images by converting it temporarily to a VDI image, compacting it, and then converting it back.

compact-vmdk.sh

#!/bin/sh -e

if [ "$#" -ne 2 ] ; then
    echo "Usage: compact-vmdk <VM_NAME> <IMAGE_PATH>"
    echo
    echo "Compacts VMDK images by converting it temporarily to a VDI image, compacting it,"
    echo "and then converting it back."
    echo
    echo "Example:"
    echo
    echo "    $ compact_vmdk boot2docker-vm '/Users/uwe/VirtualBox VMs/boot2docker-vm/boot2docker-vm.vmdk'"
    exit 1
fi

VM_NAME="$1"
IMAGE_PATH="$2"
TEMP_PATH="/tmp/image.vdi"
SIZE_BEFORE=$(du -sb "$IMAGE_PATH" | awk '{print $1}')
SIZE_AFTER=

echo "[INFO] STEP 1/7: Detaching original VM storage..."
vboxmanage storageattach "$VM_NAME" --storagectl SATA --port 1 --device 0 --type hdd --medium none

echo "[INFO] STEP 2/7: Cloning original VM image..."
vboxmanage clonehd --format vdi "$IMAGE_PATH" "$TEMP_PATH"

echo "[INFO] STEP 3/7: Deleting original VM image..."
vboxmanage closemedium disk "$IMAGE_PATH" --delete

echo "[INFO] STEP 4/7: Compacting temp VM image..."
vboxmanage modifyhd "$TEMP_PATH" --compact

echo "[INFO] STEP 5/7: Cloning temp VM image to original VM image...."
vboxmanage clonehd --format vmdk "$TEMP_PATH" "$IMAGE_PATH"

echo "[INFO] STEP 6/7: Deleting temp VM image..."
vboxmanage closemedium disk "$TEMP_PATH" --delete

echo "[INFO] STEP 7/7: Attaching original VM storage..."
vboxmanage storageattach "$VM_NAME" --storagectl SATA --port 1 --device 0 --type hdd --medium "$IMAGE_PATH"

echo "[INFO] Done."
SIZE_AFTER=$(du -sb "$IMAGE_PATH" | awk '{print $1}')
echo "Compression: $SIZE_BEFORE => $SIZE_AFTER"