[libvirt-users] Performance tuning questions for mail server

[Eric Blake]

On 10/11/2011 02:04 AM, Nicolas Sebrecht wrote:
>> 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.
>
> Which is comunterintuitive, IMHO. Admins are used to edit configuration
> files in /etc because most software are designed this way.
>
> Files not designed to be edited may stand in /var. At least, current
> files in /etc could have a header with comments from preventing manual
> edition and tips on how to deal to change configuration. ,-p

Which is exactly why newer libvirt sticks this header on such files 
(here, from /etc/libvirt/qemu/domainname.xml):

<!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
OVERWRITTEN AND LOST. Changes to this xml configuration should be made 
using:
   virsh edit domainname
or other application using the libvirt API.
-->

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