Gui Jianfeng wrote: > Igor Serebryany wrote: >> On Fri, Feb 18, 2011 at 04:12:28PM +0800, Gui Jianfeng wrote: >>> "blkio.weight" is used to control the Minimal Maximal Bandwidth. If you'd like >>> to control Max bandwidth to let your guests become I/O hungery. "blkio.throttle.*" >>> should helps. But these tunables aren't supported by blkiotune for the time being. >>> I'm considering to implement them in the future. >> I'm still a bit confused. The "weight" controls the 'percentage' of >> resources the VM gets compared to other VMs (or other processes >> participating in the cgroup)? If I have 5 processes running on the >> system, and 4 of them are VMs using cgroups, then the VMs get 4/5s of >> all CPU time for IO tasks, and each VM gets an amount of that 4/5th >> proportional to it's weight? Yes? > > Yes, if all weight are the same. I think here will be misleading. I means if VMs will get 4/5 bandwidth, the ratio of total weight of VMs and the group holds the other task should be 4:1. Thanks, Gui > >> Then, blkio.throttle can be used to set actual hard limits on IO >> consumption -- like, no more than 10Mbps for this VM. I can already do >> this with blkio cgroups, but just not from libvirt -- yes? > > yes > >> Like many people using libvirt, I only use my hosts for running VMs, and >> I am most interested in limiting IO operations per host to make sure >> that no host monopolizes our SAN. Is there a way for me to just set a >> hard IO throttle limit for libvirt as a whole which would apply to all >> child VMs created by libvirt? I saw a discussion on this list regarding >> group hierarchy, but it went over my head. > > There's no way to set this limit by libvirt. > But, I think you can set the limit by hand in cgroup directory. ;) > > Thanks, > Gui > >> --Igor > -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list