[libvirt-users] Performance tuning questions for mail server

[Eric Blake]

On 10/10/2011 03:52 PM, Alex wrote:
> I made this change by editing the xml, restarting libvirtd, then using
> virsh to define the xml file and received this message:
>
> virsh # define /etc/libvirt/qemu/bwimail02.xml
> error: Failed to define domain from /etc/libvirt/qemu/bwimail02.xml
> error: missing source information for device vda
>
> Have I done something wrong, or am I missing something?

Yes, you goofed by directly editing /etc/libvirt.  By doing that, you 
are going behind libvirt's back - if your edits happen to work, then a 
libvirtd restart will use them, but if you introduce a typo or other 
problem, then it is your fault that libvirt can't get things to work. 
If you had instead gone through the libvirt API (such as by using 'virsh 
edit bwimail02'), then libvirt would do some sanity checking up front 
and refuse to install your changes unless they were safe.

That said, your typo:

 >      <source dev='/dev/server02_vg1_2tb/lv_vm03_swap'/>

is that you used <source dev=/> instead of <source file=/>.  Even if the 
source is a raw block device on the host, you still call it out using 
file= in the xml.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org