cgroups blkio with tapdisk

[moftah moftah <mofta7y@xxxxxxxxx>]

Hi

I am facing anissue and I am not exactly sure what i am doing is the right approch

my aim is to throttle IO on tapdisk disk (xenserver/xcp-ng , the disk is nfs mounted VHD)

I tried to use cgroup blkio for that but it seems it is not working and I am not sure if blkio support this scenario or not

the steps i did are the following

1- find the tabdisk that belong to the vm I want to throttle using tap-ctl list

2- find major minor numbers using  tap-ctl list and lsblk

3- doing this command

echo "254:161 1048576" > /sys/fs/cgroup/blkio/vm.slice/blkio.throttle.write_bps_device

the tapdisk process id is already in  vm.slice

doing dd with direct flag i still get full disk write speed

any thoughts ?

Thanks