Xen devel - Apr 2010 - 4.1 feature request: block device throttling/scheduling

Hello,

This has already been added to the request list on the wiki, but I wanted to
send a quick post here as well if there were any questions or comments.

I have problems from time to time with guest VMs using up a lot more of my
storage network than I would like. More than just priority scheduling, I
would like to be able to tune how many read/write operations per second a VM
can perform. Right now, without this ability on my storage network, I can
end up having a VM that should be lower priority using up a lot of storage
IOPS and starving everything else on the storage network.

In an ideal world I could specify that vmX can perform Y writes per second
and Z reads per second (since sometimes reads can be less expensive than
writes)

Please let me know if you have any questions. Adding something like this in
would be *greatly* appreciated.

Thanks,
Thomas


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On Fri, Apr 09, 2010 at 12:13:32PM -0400, T Johnson
wrote:
>    Hello,
> 
>    This has already been added to the request list on the wiki, but I
wanted
>    to send a quick post here as well if there were any questions or
comments.
> 
>    I have problems from time to time with guest VMs using up a lot more of
my
>    storage network than I would like. More than just priority scheduling, I
>    would like to be able to tune how many read/write operations per second
a
>    VM can perform. Right now, without this ability on my storage network, I
>    can end up having a VM that should be lower priority using up a lot of
>    storage IOPS and starving everything else on the storage network.
> 
>    In an ideal world I could specify that vmX can perform Y writes per
second
>    and Z reads per second (since sometimes reads can be less expensive than
>    writes)
> 
>    Please let me know if you have any questions. Adding something like this
>    in would be *greatly* appreciated.
> 
Did you take a look at dm-ioband? 

-- Pasi


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On Fri, Apr 9, 2010 at 12:47 PM, Pasi Kärkkäinen <pasik@iki.fi> wrote:
> On Fri, Apr 09, 2010 at 12:13:32PM -0400, T Johnson wrote:
>
> >    In an ideal world I could specify that vmX can perform Y writes per
> second
> >    and Z reads per second (since sometimes reads can be less expensive
> than
> >    writes)
> >
> >    Please let me know if you have any questions. Adding something like
> this
> >    in would be *greatly* appreciated.
> >
>
> Did you take a look at dm-ioband?
>
>
> I did, but unless I''m missing something it doesn''t work
too well for
> storage networks (especially NFS) when you''re using
>
file-backed block devices. Also, I''d rather have limits on the
ops/sec
> rather than just prioritization.
>

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