Re: cannot create VM with image on zfs filesystem (zfsonlinux)

[Avi Kivity <avi@redhat.com>]

On 11/07/2011 03:57 PM, Peter Lees wrote:
> hello all
>
> when trying to create a VM using a RAW image on a zfs filesystem, i get an 
> "invalid argument" error.
>
> has anyone made this work? is it a known issue and/or is there a workaround?
>
>
>
>
> more detail:
>
> - i can create the VM on a ext4 filesystem
> - i can create the VM on a ZFS zvol ("raw" device - too slow, however)
> - linux is centos 6 (2.6.32-71.el6.x86_64 )
> - zfsonlinux is v0.6.0 (http://zfsonlinux.org)
> - qemu-kvm is v0.12.1.2 ; release  2.113.el6_0.8
> - copying the VM disk from ext4fs to zfs & then running it results in a similar error
>
>
> disk creation line was:
>
> # qemu-img create -f raw elveros_001.raw 15G
>
>
> full error was:
> Unable to complete install '<class 'libvirt.libvirtError'> internal error Process exited while reading console log output: char device redirected to /dev/pts/3
> qemu: could not open disk image /space/vm_store/elveros_001.raw: Invalid argument

I'm guessing that qemu tried to open the file with O_DIRECT, and
zfsonlinux doesn't support O_DIRECT.  Please try changing the cache mode
to writeback.

> any suggestions in getting ZFS as the vm_store, working with decent performance ?
>

zfsonlinux uses fuse, yes?  I'd be surprised if you can get decent
performance with it.

-- 
error compiling committee.c: too many arguments to function