[Engine-devel] Floating Disk feature description

[Daniel Erez]

----- Original Message -----
> From: "Yaniv Kaul" <ykaul at redhat.com>
> To: "Daniel Erez" <derez at redhat.com>
> Cc: engine-devel at ovirt.org
> Sent: Thursday, February 2, 2012 10:27:06 AM
> Subject: Re: [Engine-devel] Floating Disk feature description
> 
> On 02/01/2012 07:04 PM, Daniel Erez wrote:
> > Hi,
> >
> > Floating Disk feature description Wiki page:
> > http://www.ovirt.org/wiki/Features/DetailedFloatingDisk
> >
> > Best Regards,
> > Daniel
> > _______________________________________________
> > Engine-devel mailing list
> > Engine-devel at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/engine-devel
> 
> 0. Is it a floating disk or a floating image? would be nice to use
> the
> same terminology for all projects, where possible
> (http://www.ovirt.org/wiki/Vdsm_Storage_Terminology#Image)

Disk and Image are the same ("Disk" is the RHEV-M term for VDSM's "Image"). Both of them means: the collection of "volumes" (or, "DiskImages", in RHEV-M terminology) that comprise the full disk. We have no problem using either terminology, however might be confusing either way.
[BTW, a floating disk can't conatin snapshots - so it doesn't really matter if you are talking about disk, image, diskImage or volume - they are all the same]

> 1. I don't see why a disk name should be unique. I don't think it's
> enforceable under any normal circumstances: If user A decided to call
> his disk 'system', user B who is completely unaware of A cannot call
> his
> disk 'system' ? It should be unique at some level, but not
> system-wide.

The enforcement for uniqueness has been suggested for avoiding a list of
duplicate named disks in the Disks main tab and for identifying a specific disk.
Probelm is that any disk theoretically can be floating, so you cannot differentiate between the disks using the VM name to which it is attached, for example (moreover, some of the disks in the system are shared, so which VM name will you use?...)
Maybe we can use some other attribute for identification?

> 2. I'm not sure I understand why exporting a floating disk is 'not
> supported'. In the current design? implementation? ever?

Currently, Export is done in a VM/Template level. Support in export/import (floating) disks is a new functionality which requires additional thinking/design/etc.

> 
> Y.
>