$ sudo hdparm -Tt /dev/md0

/dev/md0:
Timing cached reads: 1458 MB in 2.00 seconds = 728.48 MB/sec
Timing buffered disk reads: 4 MB in 3.38 seconds = 1.18 MB/sec

$ time dd if=/dev/zero of=txt bs=1M count=1000
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 15.3609 s, 68.3 MB/s

real 0m15.534s
user 0m0.056s
sys 0m14.169s

可以看出对RAID 0写入1G数据所需总时间为15.534秒