Performance testing of hard disks

# mount /dev/xvdf /mnt/volume/

To perform block-level write:

# dd if=/dev/zero of=/mnt/volume/tempfile bs=1M count=1024 conv=fdatasync,notrunc

To flush caches:

echo 3 | sudo tee /proc/sys/vm/drop_caches

To perform block-level read:

# dd if=/mnt/volume/tempfile of=/dev/null bs=1M count=1024