# hdparm -tT /dev/sda

/dev/sda:
 Timing cached reads:   26304 MB in  1.99 seconds = 13220.03 MB/sec
 Timing buffered disk reads: 360 MB in  3.01 seconds = 119.54 MB/sec

# hdparm -tT /dev/sdb

/dev/sdb:
 Timing cached reads:   26240 MB in  1.99 seconds = 13186.53 MB/sec
 Timing buffered disk reads:  16 MB in  3.32 seconds =   4.82 MB/sec

# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdb2[1] sda2[0]
      243567424 blocks super 1.2 [2/1] [UU]
      bitmap: 2/2 pages [8KB], 65536KB chunk

unused devices: <none>