Scripting

Measure Disk Speed

How to measure the disk IO speed of a device under linux

Login as the root and enter the following command: 

$ sudo hdparm -tT /dev/<device>

Output:

/dev/mmcblk0: 

 Timing cached reads:   10 MB in  2.00 seconds = 5 MB/sec
 Timing buffered disk reads:  1 MB in  3.00 seconds =  1.5 MB/sec

A more accurate but possibly more damaging way :

 dd count=1k bs=1M if=/dev/zero of=/media/disk/test.img
10+0 records in
10+0 records out
10485760 bytes (100 MB) copied, 5.91082 s, 17.7 MB/s

the count parameter can be smaller than 1k, eg 500 but it needs to be quite large with an SD card to remove the effect of write caching skewing the results too much as in the example above.