[virt-tools-list] Default use of caching on raw volumes

Jamin W. Collins jcollins at asgardsrealm.net
Wed Aug 18 17:12:25 UTC 2010

On 08/18/2010 10:42 AM, Cole Robinson wrote:
> This whole exchange is moot, since the QEMU maintainer has said he'd OK a
> patch to make cache=none the default for block devices (granted others could
> object, but I think it would be accepted).

Good to hear, but do you mean accept a patch that someone else provides 
or are they going to work on the change themselves?

> virt-manager/virtinst changes the defaults in this case because it has
> information that QEMU does not: the OS being installed. However your are
> asking us to change the cache value based on the same information that QEMU
> has, overriding their default, without any sufficient reason why it's good for
> virt-manager but not good for QEMU. If it's good for both, then the proper way
> forward is to change it in QEMU.

I'm asking that the best end user experience be provided.  QEMU's own 
website makes the recommendation, I'm just asking that it be followed. 
Since the other defaults were being overridden in virt-manager (or 
virtinst) I figure that's the best place for them.  Intentionally, 
sticking with a tool's defaults when it is known that those defaults 
provide a negative experience is frankly just stubbornly stupid.  If a 
higher level tool can provide a better end user experience by overriding 
a default, it should.

Jamin W. Collins

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