[CentOS] disk on vm with kvm

Fri Jul 3 17:05:15 UTC 2020
Alexander Dalloz <ad+lists at uni-x.org>

Am 03.07.2020 um 18:54 schrieb Rick Gutierrez:
> hi list, i am trying to change the input and output scheduler on my
> disks, and it does not allow me ,
> I have several virtualized vm over kvm, and when I try to make the
> change it shows me this message:
> echo "noop" > /sys/block/vda/queue/scheduler
> -bash: echo: write error: Invalid argument
> kernel version:
> 3.10.0-1127.13.1.el7.x86_64
> any idea?

I would guess that the scheduler "noop" isn't available, thus that 
specific error message.

On my physical Server CentOS 7 with latest kernel:

# cat /sys/block/nvme0n1/queue/scheduler
[none] mq-deadline kyber

The KVM VM on that host, too CentOS 7 with latest kernel:

# cat /sys/block/vda/queue/scheduler
[mq-deadline] kyber none