The first line shows the average value since the subsystem was started, and the next report shows the average of the increments, one row per Device
device:rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await SVCTM%util
SDA 0.00 23.75 0.00 5.79 0.00 236.33 40.83 0.02 3.10 0.76 0.44
Dm-0 0.00 0.00 0.00 29.54 0.00 236.33 8.00 0.11 3.56 0.15 0.44
Dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
rrqm/s wrqm/s
Merged read and write requests per second, "merged" means that the operating system takes multiple logical requests from the queue to merge into a single request to the actual disk
r/s W/S Read and write requests sent to the device per second
RSEC/S wsec/s number of reads and writes per second, some systems are also output to rkb/s and wkb/s, which means the number of kilobytes per second read and write
AVGRQ-SZ number of sectors requested
Avgqu-sz number of requests waiting in the device queue-----------didn't understand.
The number of milliseconds spent waiting on a disk
SVCTM the number of milliseconds that the service request took, not including the queue time-------execution time?
%util percentage of time spent at least one active request ——-----------didn't understand.