Single Disk Snapshot Feature

[Daniel Erez]

----- Original Message -----
> From: "Malini Rao" <mrao at redhat.com>
> To: "Daniel Erez" <derez at redhat.com>
> Cc: arch at ovirt.org
> Sent: Monday, January 6, 2014 9:09:44 PM
> Subject: Re: Single Disk Snapshot Feature
> 
> Daniel,
> 
> I went through the feature page and I have some questions ( mainly from the
> user experience perspective) that may be about the feature or about
> snapshots itself..not sure -
> 
> 1. Will the ability to choose disks be available only when I click on 'Create
> Snapshot' button on the tool bar or even when I right click an existing
> snapshot and trigger the create snapshot flow?

Disks selection will be available only when creating a new snapshot.
Currently, editing an existing snapshot is not applicable.

> 
> 2. I am a little concerned about the Custom preview option in terms of how
> intuitive that might be. Would it be more intuitive if there was a way for
> the user to select multiple snapshots in the list and then click preview to
> get all those selected snapshots as rows with disk selection possible? My
> concern is that even though 'Preview' and 'Custom preview' are presented
> together, they behave differently - preview will send them to the preview
> flow for that single snapshot while, the custom preview dialog is really
> independent of any row selection of the snapshot list. If the multiple
> selection option I described will not work for any reason, then I think
> having a separate button with a more descriptive name such as 'Hybrid
> Snapshot' might help.

You're right, I was concerned as well regarding the non-reliance of
the custom button and row selection. However, currently, multiple
selection is not relevant for any other action (i.e. multiple selection
will enforce graying out all the others buttons). In addition, I'm not
sure it would be more intuitive for the user to select more than one snapshot
just for doing a custom preview (as for now, multiple selection is prohibited
in this sub-tab). Do you think that separating to a different (regular)
action button could work better here? (btw, not sure about 'Hybrid Snapshot'
as the dialog is actually invoking only a preview of a snapshot rather
than creating one. 'Hybrid Preview' sounds good? :)

> 
> 3. In the custom preview dialog, what is the column with the radio button and
> is that somehow related with row selection? Right now, it is creating
> confusion for me because it seems like I pick a snapshot with this radio
> button in addition to the row highlighting and then that expectation falls
> apart since I am able to select across rows on the disks columns. Maybe what
> is needed here is to remove the row highlighting for starters and also pull
> out the display(?) column out of the list and have a single select drop down
> at the bottom of the dialog so that in the grid, all you are doing is disk
> selection. Or maybe at least move the radio button column to the right, so
> it doesn't confuse with selection.

The radio button column is for the snapshot's 'VM configuration' which 
consists of the other attributes of a VM. E.g. name/description/cpu/nics/apps/etc.
I.e. this dialog allows mix-n-match only for the disks, other components
of the snapshot aren't configurable.
So a single drop down won't work here as every snapshot might contain
a different VM configuration, from which the user can choose.
Regarding the row selection - you're right, I've been already told it's
quite confusing. I removed it from my implementation drafts but just
hadn't have a chance to update the video yet...

> 
> 4. Also, I wanted to know how many disks can we expect per row on an avg? I
> ask to see if the matrix format is the most suitable or if we need to think
> of other layouts...

We've tried a few variations scrolling for the dialog, e.g. keeping the
left hand columns (Date/Name/VM configuration) static and allow 
horizontal scrolling only for the disks. But it seems that for
most use-cases, we'll have many snapshots and only a few disks.
Hence, it'll probably better ux-wise to keep the dialog cleaner
and simpler for the common use-cases while supporting rare
scenarios with (regular) scrollbars for the entire table.

Let me know what you think, thanks a lot for the feedback!

> 
> Thanks
> Malini
> 
> ----- Original Message -----
> From: "Daniel Erez" <derez at redhat.com>
> To: arch at ovirt.org
> Sent: Sunday, December 15, 2013 12:40:06 PM
> Subject: Single Disk Snapshot Feature
> 
> Hi,
> 
> "Single Disk Snapshot" feature is targeted to 3.4.
> Please review the wiki page [1] and feel free to
> share your thoughts.
> 
> [1] http://www.ovirt.org/Features/Single_Disk_Snapshot
> 
> Regards,
> Daniel
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