rrqm/s & wrqm/s always zero

Hello,

On RHEL 6, iostat -dkNx 2 shows that rrqm/s & wrqm/s is always zero. What could be the reason?

Its a 12c RAC system with disks in ASM and the server is pretty busy.

I am suspecting that either iostat is reporting incorrectly, possibly due to a bug OR may be there is some performance configuration (may be IO scheduler bug or driver bug) because of which this is happening.

Does anybody have experienced this?

Thanks