Re: [fedora-virt] images on tmpfs?

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On 06/05/2014 10:13 AM, Tom Horsley wrote:
> Anyone know why qemu wouldn't want to run a virtual
> machine installing to a qcow2 image file on a tmpfs
> filesystem?
>
> They are doing a lot of test installs in virtual machines
> at work, and I suggested creating a storage pool
> in tmpfs (the host machine has vast amounts of memory)
> as something that might make the install go faster,
> but it seems to refuse to even attempt to use the
> tmpfs image.

What caching mode are you requesting? tmpfs can't (yet) support
O_DIRECT, and if the caching mode you request causes qemu to try
O_DIRECT, that would explain why it is failing.

--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org