16gb sd card+16gb usb flash disk Raid 0 Raspbery Pi 2 root@raspberry:~# hdparm -t /dev/md127 /dev/md127: Timing buffered disk reads: 114 MB in 3.03 seconds = 37.68 MB/sec root@raspberry:~# hdparm -T /dev/md127 /dev/md127: Timing cached reads: 670 MB in 2.00 seconds = 334.32 MB/sec root@raspberry:~# ...