Here's the problem :
We have a busy KVM host. Sometimes, we need to make a copy or to clone a VM. Or we schedule a weekly backup of our VMs.
When that happens, iowait jumps, the host gets busy and the other VMs start suffering too for 10 or 15 minutes. Not too good for websites responsiveness.
Would it be possible to choose wether or not to limit dd speed, using for exemple "cpipe -s " ? Copying a volume would take longer, but dd would leave io ressources for other processes.
Thanks in advance,