Trigger internal trim on SF volume

fake_trim.sh

if [ $# -ne 3 ]; then
        echo
        echo "Usage: $0 <filename> <size> <device>"
        echo
        echo "<filename> is a temporary file for the test"
        echo "<size> is the file size in MB NOTE, this needs to be very large on the order of free-capacity - safetyBuffer"
        echo "<device> is the device being trimmed, e.g. /dev/vda"
        echo
        echo "Example: $0 tempfile 5 /dev/vda"
        echo
        echo "This would run the test for /dev/vda creating a"
        echo "temporary file named \"tempfile\" with 5 MB"
        echo
        exit 1
fi

FILE="$1"
SIZE=$2
DEVICE="$3"

# Create the temporary file
dd if=/dev/zero of="$FILE" count=1 bs=${SIZE}M oflag=direct
sync

# Get the address of the first sector
# This is optional, were were using this just for verification
hdparm --fibmap "$FILE"
SECTOR=`hdparm --fibmap "$FILE" | tail -n1 | awk '{ print $2; }'`

# Delete the file and read the sector
rm -f $FILE
sync
echo
echo "File deleted. Sleeping for 120 seconds before re-reading the sector."
echo "If TRIM is working, you should see all 0s now."
sleep 120
hdparm --read-sector $SECTOR "$DEVICE"
echo
echo "If the sector isn't filled with 0s, something is wrong with your"
echo "configuration. Try googling for \"TRIM SSD Linux\"."
echo

exit 0