[libvirt] libvirt / virt-manager issue with NFS share as storage plus a philosophy question - resend w/subject

[Daniel P. Berrange]

On Tue, May 05, 2009 at 02:40:54PM -0500, mike.hinz at yr20.com wrote:
> 
> Now comes the philosophy piece:  It seems like that the way that 
> libvirt and virt-manager want to handle storage is to be able to 
> fully control the mounting process.  That seems to me to be a 
> very nice thing as you have a single way to manage storage along
> with your VMs.  However, at least with respect to NFS, there are
> a number of parameters that people might need to give to the mount
> command for things like performance optimization and who knows 
> what else.  Note that this is a consideration completely aside 
> from the bug issue above.  It seems to me that either you have 
> to just use the user created mount points, either manually or 
> by fstab OR you have to allow all the possible options to be 
> passed if you want to fully control the process.  Right now, it's
> tricky to do, if you want to get paras passed for tuning or 
> whatever and requires some tricky handwork to get it done.  

One of the design goals when we added the storage APIs, was that it
should not require any direct admin modification of config files to
setup individual storage pool. So the XML format is intended to 
contain enough information to cope with the 95% of common cases.
The other general libvirt design goal is that the same XML formats 
should be applicable to any OS/backend on which the APIs are to be
implemented, so avoiding Linux-isms is desirable. 

Thus we'd prefer not to add capability to pass arbitrary linux
mount command line options in via the XML. We could identify some
set of options that are important and define a formal portable 
representation for them in the XML, and map that to the OS-specific
mount flags internally

NB, if you have user created mount points, then you can already
use them, just defining a plain directory storage pool - this 
will just accessing files in the pre-existing directory and not
try todo any of the mount/unmount steps. 


Daniel
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