use vmstat command to know about disk access

I love to use vmstat command to measure load of servers. But, to check disk-intensive overload, usual vmstat output is not device-specific.

$ vmstat 5
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
r b swpd free buff cache si so bi bo in cs us sy id wa st
0 0 25924 11324 3524 135644 0 0 3 20 1 4 0 0 100 0 0
0 1 25924 11324 3528 135640 0 0 0 6 19 33 0 0 100 0 0
0 0 25924 11324 3532 135644 0 0 0 1 18 34 0 0 100 0 0


So, I looked into /proc/diskstats , but it is cryptic.

$ cat /proc/diskstats
1 0 ram0 0 0 0 0 0 0 0 0 0 0 0
1 1 ram1 0 0 0 0 0 0 0 0 0 0 0
1 2 ram2 0 0 0 0 0 0 0 0 0 0 0
1 3 ram3 0 0 0 0 0 0 0 0 0 0 0
1 4 ram4 0 0 0 0 0 0 0 0 0 0 0
1 5 ram5 0 0 0 0 0 0 0 0 0 0 0
1 6 ram6 0 0 0 0 0 0 0 0 0 0 0
1 7 ram7 0 0 0 0 0 0 0 0 0 0 0
1 8 ram8 0 0 0 0 0 0 0 0 0 0 0
1 9 ram9 0 0 0 0 0 0 0 0 0 0 0
1 10 ram10 0 0 0 0 0 0 0 0 0 0 0
1 11 ram11 0 0 0 0 0 0 0 0 0 0 0
1 12 ram12 0 0 0 0 0 0 0 0 0 0 0
1 13 ram13 0 0 0 0 0 0 0 0 0 0 0
1 14 ram14 0 0 0 0 0 0 0 0 0 0 0
1 15 ram15 0 0 0 0 0 0 0 0 0 0 0
202 0 xvda 1900702 111759 57624068 22798740 21260401 21742422 344022684 149429332 0 25033876 172228060
202 1 xvda1 1178 2366 2 4
202 2 xvda2 2011295 57621462 43002835 344022680
253 0 dm-0 2002226 0 57550986 23818188 42992837 0 343942696 261736148 0 25033368 285554312
253 1 dm-1 8752 0 70016 102772 9998 0 79984 347408 0 16320 450180
9 0 md0 0 0 0 0 0 0 0 0 0 0 0

Then, I come back to vmstat with "-d" option. Just to see formatted information of /proc/diskstats.

$ vmstat -d
disk- ------------reads------------ ------------writes----------- -----IO------
total merged sectors ms total merged sectors ms cur sec
ram0 0 0 0 0 0 0 0 0 0 0
ram1 0 0 0 0 0 0 0 0 0 0
ram2 0 0 0 0 0 0 0 0 0 0
ram3 0 0 0 0 0 0 0 0 0 0
ram4 0 0 0 0 0 0 0 0 0 0
ram5 0 0 0 0 0 0 0 0 0 0
ram6 0 0 0 0 0 0 0 0 0 0
ram7 0 0 0 0 0 0 0 0 0 0
ram8 0 0 0 0 0 0 0 0 0 0
ram9 0 0 0 0 0 0 0 0 0 0
ram10 0 0 0 0 0 0 0 0 0 0
ram11 0 0 0 0 0 0 0 0 0 0
ram12 0 0 0 0 0 0 0 0 0 0
ram13 0 0 0 0 0 0 0 0 0 0
ram14 0 0 0 0 0 0 0 0 0 0
ram15 0 0 0 0 0 0 0 0 0 0
xvda 1900690 111759 57623940 22798620 21260398 21742409 344022556 149429324 0 25033
dm-0 2002214 0 57550858 23818068 42992821 0 343942568 261736088 0 25033
dm-1 8752 0 70016 102772 9998 0 79984 347408 0 16
md0 0 0 0 0 0 0 0 0 0 0