datastore garbage collection

My instance had 12GB datastore
$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda5             169G   73G   88G  46% /
none                  5.9G  672K  5.9G   1% /dev
none                  5.9G  196K  5.9G   1% /dev/shm
none                  5.9G  104K  5.9G   1% /var/run
none                  5.9G     0  5.9G   0% /var/lock
/dev/sda2              98G   12G   81G  13% /mnt/datastore


I ran datastore garbage collection, which ran for 5 hours. and it's now 2GB:
 $ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda5             169G   73G   88G  46% /
none                  5.9G  672K  5.9G   1% /dev
none                  5.9G  296K  5.9G   1% /dev/shm
none                  5.9G  108K  5.9G   1% /var/run
none                  5.9G     0  5.9G   0% /var/lock
/dev/sda2              98G  2.0G   91G   3% /mnt/datastore

I have datastore out of crx-quickstart on a different drive for easy back up.. etc.
    <DataStore class="com.day.crx.core.data.ClusterDataStore">
        <param name="path" value="/mnt/datastore"/>
    </DataStore>


The script for running datastore garbage collection is here: