[libvirt-users] domain disk io throttling

[Edoardo Comar]

Hi
Currently <blkiotune> in domain xml allows only to set cgroups weights
 blkio.weight or blkio.weight_device

I see from 
https://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt 

that cgroups also allows throttling policies settable via 
 blkio.throttle.read_bps_device
- blkio.throttle.write_bps_device
- blkio.throttle.read_iops_device
- blkio.throttle.write_iops_device

these AFAIK are not the ones set via <blkdeviotune> which need to be 
applied to individual virtual disks.

are there any plans to allow libvirt to make use of the cgroup throttling?
it looks to me it could make life simpler by assigning a bandwitdh limit 
to a domain 
without having to partition it among its multiple virtual disks.

Assigning a limit to the domain is useful from a host resource management 
perspective, 
while having to dictate how guests use their individual disks is not, I 
think.

--------------------------------------------------
regards,
Edoardo Comar
WebSphere Application Service Platform for Networks (ASPN)
ecomar at uk.ibm.com
+44 (0)1962 81 5576 
IBM UK Ltd, Hursley Park, SO21 2JN

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