Thanks for the feedback.
At first it looked fine, but then I realized the column sorting is random, for example this is the output from 2 different ESXi Host:
HostA
VM Instance1 write1 numberwrite1 numberread1 read1 Instance2 write2 numberwrite2 numberread2 read2
HostB
VM Instance1 numberwrite1 write1 read1 numberread1 Instance2 numberwrite2 write2 read2
Can we sort the columns with a recurrent pattern ? Then I can parse the results using regex later on for field extraction.