[libvirt] [RFC PATCH 0/5] Summary on QEMU I/O throttling support to libvirt

[Stefan Hajnoczi]

Jianfeng and Hu Tao,
Just want to draw your attention to this thread if you haven't seen it
:).  Your review and thoughts on I/O throttling in libvirt would be
appreciated.

Stefan

On Mon, Oct 10, 2011 at 2:45 PM, Lei Li <lilei at linux.vnet.ibm.com> wrote:
> Today libvirt supports the cgroups blkio-controller, which handles
> proportional shares and throughput/iops limits on host block devices.
> blkio-controller does not support network file systems (NFS) or other
> QEMU remote block drivers (curl, Ceph/rbd, sheepdog) since they are
> not host block devices. QEMU I/O throttling works with all types of
> drive and can be applied independently to each drive attached to
> a guest and supports throughput/iops limits.
>
> To help add QEMU I/O throttling support to libvirt, we plan to complete
> it with add new API virDomainBlockIoThrottle(), new command 'blkiothrottle'
> and Python bindings.
>
> Notes: we are sending this series out now(even though they are not completed
> yet.)because we want to start the review process. These patches implemented
> the below features by Zhi Yong Wu:
>
> 1) Enable the blkio throttling in xml when guest is starting up.
>
> Add blkio throttling in xml as follows:
>
>    <disk type='file' device='disk'>
>      <driver name='qemu' type='raw'/>
>      <source file='/var/lib/libvirt/images/kvm-one.img'/>
>      <target dev='vda' bus='virtio'/>
>      <address type='pci' domain='0x0000' bus='0x00' slot='0x05'
> function='0x0'/>
>      <iothrottle bps='100000' bps_rd='20000'.../>
>    </disk>
>
> 2) Enable blkio throttling setting at guest running time.
>
> virsh blkiothrottle<domain>   <device>   [--bps<number>] [--bps_rd<number>]
> \
> [--bps_wr<number>] [--iops<number>] [--iops_rd<number>] [--iops_wr<number>]
>
> [PATCH 1/5] Add new API virDomainBlockIoThrottle.
> [PATCH 2/5] Add virDomainBlockIoThrottle support to the remote driver.
> [PATCH 3/5] Implement virDomainBlockIoThrottle for the qemu driver.
> [PATCH 4/5] Enable the virDomainBlockIoThrottle API in virsh.
> [PATCH 5/5] Enable virDomainBlockIoThrottle in the python API.
>
> And I will address feedback and work on the missing features in few days
> includes:
>
> 3) The support to display the setting for block i/o throttling - HMP/QMP
> 4) Python binding support.
> 5) --current --live --config options support to unify the libvirt API.
>
>
>
> --
> Lei
>
>
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