[ovirt-devel] Gluster Volume Snapshots - Feature review

Alok Srivastava asrivast at redhat.com
Mon Jan 12 05:54:26 UTC 2015 


----- Original Message -----
From: "Shubhendu Tripathi" <shtripat at redhat.com>
To: "Einav Cohen" <ecohen at redhat.com>, "Alok Srivastava" <asrivast at redhat.com>
Cc: devel at linode01.ovirt.org, "rhsc-dev" <rhsc-dev at redhat.com>
Sent: Thursday, January 1, 2015 11:30:41 PM
Subject: Re: [ovirt-devel] Gluster Volume Snapshots - Feature review

On 01/01/2015 10:36 PM, Einav Cohen wrote:
>> ----- Original Message -----
>> From: "Shubhendu Tripathi" <shtripat at redhat.com>
>> Sent: Thursday, January 1, 2015 10:05:48 AM
>>
>> On 12/31/2014 11:42 PM, Einav Cohen wrote:
>>> Thanks, Shubhendu. Additional comments:
>>>
>>>> ...
>>>> Yes, attempt to create second snapshot schedule is actually an override
>>>> option. Of course spot creation is allowed in addition to the scheduled.
>>>> ...
>>>> ...
>>>> If the option Volumes -> Snapshots -> New selected, the dialog opens
>>>> with pre-populated snapshot name prefix and Recurrence type selected as
>>>> None by default. This effectively is one time snapshot creation.
>>>> If this is first time and user wants to schedule the snapshot creation,
>>>> he/she can change the recurrence type and provide details. Snapshot
>>>> creation is scheduled in this case.
>>>> Later, it user wants to edit the schedule, he/she needs to select option
>>>> Volumes -> Snapshots -> Schedule (may be for this reason only I want to
>>>> call it Edit Schedule). So effectively option Volumes -> Snapshots ->
>>>> Schedule is meant for only re-scheduling the snapshot creation. If its
>>>> not yet scheduled dialog opens with recurrence type selected as None.
>>>> ...
>>>   From your latest responses, I conclude the following.
>>>
>>> via the "New" dialog, you can:
>>>
>>> (1) create a one-time snapshot
>>> (2) create a new snapshot schedule
>>> (3) override (and practically, edit) an existing snapshot schedule
>>>
>>> via the "Schedule" dialog, you can:
>>>
>>> (a) create a one-time snapshot (by selecting the 'None' recurrence)
>>> (b) create a new snapshot schedule (by selecting something other than
>>> 'None' in the recurrence field, given that no schedule exists yet)
>>> (c) edit an existing snapshot schedule (which is what this dialog is
>>> actually meant to do).
>>>
>>> I am not sure about (a), but it doesn't matter much for my point: "New"
>>> and "Schedule" have the exact same functionality. To be more accurate:
>>> "New" contains all of the needed functionality; "Schedule" is not really
>>> needed. The only thing that "New" is potentially missing is showing the
>>> values of the already-existing snapshot schedule, if one exists.
>>>
>>> I think that this may confuse to the user; I recommend to either
>>> unite both of these actions/dialogs to a single action/dialog, or
>>> separate completely some functionalists.
>>>
>>> So my recommendation is to do one of the following:
>>>
>>> (a) unite:
>>> Have a single action ("Create / Schedule") which will display a
>>> dialog very similar to the "New" dialog, with the option to see the
>>> values of the already-existing snapshot schedule, if one exists.
>>> In this case, I would actually recommend to go with something more
>>> similar to option 2 in http://i.imgur.com/4j7hvRY.png, rather than
>>> option 3 (so the separation between *creating new* *one-time*
>>> snapshot and *editing an existing* *scheduled* snapshot is clearer).
>>> see http://i.imgur.com/ZgCp9Tz.png for an updated suggestion.
>>>
>>> - or -
>>>
>>> (b) separate:
>>> Have two completely separate actions: "Create Now" and "Schedule".
>>>
>>> - The "Create Now" dialog will look like the 'General' side-section
>>> of the "New" dialog (i.e. without the "Schedule" side-section;
>>> it will allow only one-time immediate snapshot creation.
>>>
>>> - The "Schedule" dialog will look like the "New" dialog (with both
>>> 'General' and 'Schedule' side-sections) without the "None" recurrence,
>>> and will allow only creating a new recurring snapshot schedule (if one
>>> doesn't exist yet) or editing the existing schedule (in this case, the
>>> dialog would be pre-populated with the values of the existing schedule).
>>>
>>> I am more in favor of (b) - it seems simpler and more user-friendly in
>>> my view.
>> Option (b) is something which we had started with, then at later stage
>> it was discussed that scheduling as well should be in the flow of
>> creation of snapshot so merged with New Snapshot option. After this as
>> we need Edit option for snapshot schedule, so introduced Schedule option.
>>
>> But still, as you suggest I feel option (b) is no doubt a clearer and
>> user friendly way.
>>
>> Alok, need a point of view from PMs on this.
> Thanks, Shubhendu.
>
> @Alok (and all):
> the main pain-point in the current design that I am trying to address is
> the fact that in the 'New' dialog, you have the option to create a one-
> time snapshot, and within the same dialog, with a very small (too small
> IMO) change, you have the option to edit (override) an already-existing
> schedule, without even realizing necessarily that you are editing
> something (since you are in a 'New' dialog) and without seeing the values
> of the object that you are editing. From a UX perspective, this may be
> confusing and misleading.
>
> if it is imperative to combine the one-time creation functionality with
> the scheduling functionality, you have option (a).
>
> here is another option (c) that will allow you to create a one-time
> snapshot and *create* a new schedule in the same dialog.
> it is also probably the closest option to the original design in the
> wiki, so I encourage you to consider it:
>
> (c) Have two options, "New" and "Schedule", like today.
>
> - "New" will be *only* for creating new objects, not editing/overriding
> existing ones. It will look very similar to "New" in the current design,
> including the "None" recurrence that I have suggested before.
>
>   * In case a schedule doesn't exist yet - "New" will have both the
> 'General' and 'Schedule' sections, like today, allowing creating a one-
> time snapshot as well as creating a new snapshot schedule.
>
>   * In case a schedule already exists - "New" will have only the 'General'
> side-section (the 'Schedule' side-section will not be displayed), allowing
> only creation of new one-time snapshots.
>
> - "Schedule":
>
>   * In case a schedule doesn't exist yet - two options:
>
>      i.  disable this button (i.e. force the user to create a new schedule
> via "New"); in this case, I agree with Shubhendu on renaming the button to
> "Edit Schedule".
>
>     - or -
>
>      ii. have the dialog look exactly like "New" today, without the "None"
> recurrence option; so only new schedule can be created, not one-time
> snapshots. One-time snapshots should be created only via "New".
>
>   * In case a schedule already exists - the dialog will look like "New",
> without the 'General' section (i.e. very similar to the mock-up of the
> "Schedule" dialog in the ovirt wiki today), pre-populated with the current
> values of the existing schedule.
>
> Your thoughts/comments are welcome. Thank you.

So if we go ahead with above mentioned option (c) with "Edit Schedule" 
option it would be something as below.

- Have two optiona "New" and "Edit Schedule" under Volumes -> Snapshots.

- "New" will be *only* for creating new objects, not editing/overriding
existing ones.

  * In case a schedule doesn't exist yet - "New" will have both the
'General' and 'Schedule' sections, like today, allowing creating a one-
time snapshot as well as creating a new snapshot schedule.

  * In case a schedule already exists - "New" will have only the 'General'
side-section (the 'Schedule' side-section will not be displayed), allowing
only creation of new one-time snapshots.

- "Edit Schedule":

  * In case a schedule doesn't exist yet - disable this button (i.e. force the user to create a new schedule
via "New")

  * In case a schedule already exists - the dialog will look like "New",
without the 'General' section (i.e. very similar to the mock-up of the
"Schedule" dialog in the ovirt wiki today), pre-populated with the current
values of the existing schedule.

@Alok, need your confirmation. This option certainly looks clean to me personally but leave the final call to your descretion.

Alok:@Shubhendu,Thanks for your time to explain these points in meeting on 08/01. This looks good.
Regards,
Shubhendu

>
>>
>>> Your comments/thoughts are welcome.
>>>
>>> Thanks!
>>>
>>> ----
>>> Regards,
>>> Einav
>>>
>>> ----- Original Message -----
>>>> From: "Shubhendu Tripathi" <shtripat at redhat.com>
>>>> To: "Einav Cohen" <ecohen at redhat.com>
>>>> Cc: devel at linode01.ovirt.org, "rhsc-dev" <rhsc-dev at redhat.com>
>>>> Sent: Wednesday, December 31, 2014 12:56:44 AM
>>>> Subject: Re: [ovirt-devel] Gluster Volume Snapshots - Feature review
>>>>
>>>> Hi Einav,
>>>>
>>>> Find the comments inline.
>>>>
>>>> Thanks and Regards,
>>>> Shubhendu
>>>>
>>>> On 12/30/2014 11:13 PM, Einav Cohen wrote:
>>>>> Thank you, Shubhendu! I have a few more comments:
>>>>>
>>>>>> Yes that's true for most of the cases. But having Options setting from
>>>>>> sub-tab, not sure if that's correct. May be "New" is fine.
>>>>> I think that if a user already got to the "Snapshots" sub-tab of a
>>>>> specific Volume, it would seem strange that not all Snapshots-related
>>>>> actions for that Volume are available from there - but I will leave it
>>>>> to your discretion; I think that "New" is indeed the most important one
>>>>> to have also in the sub-tab.
>>>> We may have the New option available under sub tab as well. Setting
>>>> configuration options would only be available in Volumes main tab.
>>>>
>>>>>> Once scheduled the only way to stop snapshot creation is to provide an
>>>>>> end date.
>>>>> let me try and understand what are the exact snapshot creation
>>>>> capabilities.
>>>>> consider the following use-cases (which may make absolutely no sense,
>>>>> just giving these as examples in order to understand the capabilities):
>>>>>
>>>>> (1) let's say that I want to do two recurring snapshots schedules in
>>>>> parallel for a single volume: one Monthly, and another one Weekly.
>>>>> Can I do that?
>>>> We can have only one schedule for a volume at a time.
>>>>
>>>>> I am assuming that I can't, i.e. there can only be one
>>>>> recurring-snapshot-
>>>>> creation schedule per volume (which you create via "New" and edit via
>>>>> "Schedule") - is that correct? If so: are you blocking an attempt to
>>>>> create a "New" recurring snapshot schedule when one already exists for
>>>>> this Volume (e.g. disable the "New" button, fail a CanDoAction with a
>>>>> message such as "Cannot create snapshot scheduling. A snapshot scheduling
>>>>> already exists for this Volume", etc.) or allowing override of the
>>>>> already-
>>>>> existing schedule (with a proper warning)?
>>>> Even if a volume snapshot creation is scheduled user can still opt for
>>>> onetime spot snapshot creation and New would be available.
>>>>
>>>>> If my assumption is wrong, and I can have two (or more) recurring-
>>>>> snapshot-creation schedules per volume: how do I *edit* these schedules?
>>>>> what happens when I click on "Schedule"? which one of the two schedules
>>>>> will I edit? The Weekly one? The Monthly one?
>>>> As there is only one schedule for a volume at a time, so this is not
>>>> valid scenario. Exiting single instance of schedule can be edited using
>>>> the option Volumes -> Snapshots -> Schedule. May be if you suggest this
>>>> option can be renamed to "Edit Schedule".
>>>>
>>>>> If I am comparing the terminology to the one of Calendar meeting schedule
>>>>> (see http://i.imgur.com/xvf5w30.png): I don't have any "series" objects
>>>>> that I can 'edit', I can see only "instances", and I can edit only one
>>>>> "global" 'series' object via the "Schedule" button.
>>>>> [again: if there can only be one recurring-snapshot-creation schedule per
>>>>> volume, then the current design is OK, assuming the attempt to create a
>>>>> second snapshot-schedule for a volume is properly blocked/overridden/...]
>>>> Yes, attempt to create second snapshot schedule is actually an override
>>>> option. Of course spot creation is allowed in addition to the scheduled.
>>>>
>>>>> (2) let's say that I want to do a weekly recurring snapshot scheduling
>>>>> for
>>>>> a certain volume. In addition to that weekly recurring snapshots, I want
>>>>> to take a one-time snapshot of this volume right now. Can I do that?
>>>> Yes, as discussed above stop one time creation in addition to the
>>>> scheduled is allowed.
>>>>
>>>>> If so: then my suggestion [http://i.imgur.com/4j7hvRY.png, option 3] is
>>>>> indeed valid; I am assuming that the user can create, per volume: one
>>>>> recurring snapshot schedule + unlimited one-time snapshots.
>>>> Yes. That's correct.
>>>>
>>>>> [If the user can create two (or more) recurring snapshot schedules - see
>>>>> (1) above].
>>>>> need to make sure that the user is able to create a "New" snapshot with
>>>>> the "Weekly" recurrence schedule, and then another "New" snapshot(s) with
>>>>> the "None" recurrence schedule, which will create the one-time
>>>>> snapshot(s)
>>>>> immediately, and that the schedule of the Weekly snapshot can be edited
>>>>> via the "Schedule" option.
>>>> So it goes like this. Say a Weekly snapshot is scheduled for certain
>>>> volume and later user wants to create single on-spot snapshot. For this
>>>> he/she need to select the option Volumes -> Snapshots -> New and not
>>>> Volumes -> Snapshots -> Schedule. By default the option None is selected
>>>> as Recurrence type and it creates a one time snapshot. Still the
>>>> schedule stands valid in the system and if the user wants to edit the
>>>> schedule he/she need to select the option Volumes -> Snapshots ->
>>>> Schedule. Hope this clarifies.
>>>>
>>>>> If not (i.e. the user can create only one recurring snapshot schedule,
>>>>> and that's it - no additional recurring snapshot schedules, no one-time
>>>>> immediate snapshots, etc.), then my suggestion is invalid, and a 'None'
>>>>> recurrence is not needed.
>>>> As said above, one time snapshot creation is still allowed in addition
>>>> to the scheduled. (Using Volumes -> Snapshots -> New option)
>>>>
>>>>> In this case, just need to make sure that the 'Schedule' side-section of
>>>>> the dialog will be pre-populated with the most common/reasonable
>>>>> recurrence
>>>>> schedule, in case the user will not touch it.
>>>>> BTW, if this is indeed the case, then there is probably no need for both
>>>>> 'New' and 'Schedule' buttons - only 'Schedule' is sufficient.
>>>>>
>>>>>> Accept. The snapshot create dialog itself can be used here.
>>>>> Just need to make sure to change its title accordingly (to 'Schedule
>>>>> Snapshot' or something similar; right now it says "New Snapshot" in
>>>>> the wiki).
>>>>>
>>>>> I assume that this dialog can be used for:
>>>>>
>>>>> (a) creating a New snapshot schedule (which should look very similar
>>>>> to the 'New Snapshot' dialog, maybe with some pre-populated values,
>>>>> maybe without the 'None' option in the Recurrence drop-down).
>>>> If the option Volumes -> Snapshots -> New selected, the dialog opens
>>>> with pre-populated snapshot name prefix and Recurrence type selected as
>>>> None by default. This effectively is one time snapshot creation.
>>>> If this is first time and user wants to schedule the snapshot creation,
>>>> he/she can change the recurrence type and provide details. Snapshot
>>>> creation is scheduled in this case.
>>>> Later, it user wants to edit the schedule, he/she needs to select option
>>>> Volumes -> Snapshots -> Schedule (may be for this reason only I want to
>>>> call it Edit Schedule). So effectively option Volumes -> Snapshots ->
>>>> Schedule is meant for only re-scheduling the snapshot creation. If its
>>>> not yet scheduled dialog opens with recurrence type selected as None.
>>>>
>>>>> - and/or -
>>>>>
>>>>> (b) editing the already-existing schedule (in this case, fields that
>>>>> cannot be edited should be disabled).
>>>> As above.
>>>>
>>>>> I hope I was clear - please let me know if you have any questions or
>>>>> comments.
>>>>>
>>>>> Thanks again!
>>>>>
>>>>> ----
>>>>> Regards,
>>>>> Einav
>>>>>
>>>>> ----- Original Message -----
>>>>>> From: "Shubhendu Tripathi" <shtripat at redhat.com>
>>>>>> To: "Einav Cohen" <ecohen at redhat.com>
>>>>>> Cc: devel at linode01.ovirt.org, "rhsc-dev" <rhsc-dev at redhat.com>
>>>>>> Sent: Tuesday, December 30, 2014 7:09:51 AM
>>>>>> Subject: Re: [ovirt-devel] Gluster Volume Snapshots - Feature review
>>>>>>
>>>>>> Thanks Einav for the detailed review and your comments.
>>>>>> Find below the comment inline.
>>>>>>
>>>>>> Will update the wiki accordingly and circulate.
>>>>>>
>>>>>> Team, please provide your thoughts (if conflicting) on this.
>>>>>>
>>>>>> Thanks and Regards,
>>>>>> Shubhendu
>>>>>>
>>>>>> On 12/30/2014 05:33 AM, Einav Cohen wrote:
>>>>>>> Hi Shubhendu,
>>>>>>>
>>>>>>> First of all - very detailed wiki pages (I focused mainly on the
>>>>>>> User Experience part) - nicely done.
>>>>>>>
>>>>>>> I have a couple of comments / suggestions regarding the GUI:
>>>>>>>
>>>>>>> Snapshot action-group:
>>>>>>>
>>>>>>> - from the wiki page:
>>>>>>> """
>>>>>>> A new action-group "Snapshot" would be introduced under actions
>>>>>>> for a volume.
>>>>>>> """
>>>>>>> I assume that you will implement it similarly to the "Power Management"
>>>>>>> action-group (on Hosts main tab) or the "Profiling" action-group (on
>>>>>>> the Volumes tab), i.e. with a drop-down-like styling
>>>>>>> [http://i.imgur.com/eWRg6o8.png]?
>>>>>> Yes. That's correct.
>>>>>>
>>>>>>> - If the Snapshot-related actions are expected to be core/critical in
>>>>>>> the Volumes-related workflows, it makes sense to put them in the main-
>>>>>>> tab, but please consider adding them to the Snapshots sub-tab as well,
>>>>>>> in order to be consistent with other similar oVirt workflows.
>>>>>> Yes that's true for most of the cases. But having Options setting from
>>>>>> sub-tab, not sure if that's correct. May be "New" is fine.
>>>>>>
>>>>>>> New Snapshot dialog -> Schedule section:
>>>>>>>
>>>>>>> - I suggest to implement the time-interval selection with a drop-down,
>>>>>>> rather than a radio-button group; it is more consistent with e.g.
>>>>>>> event-repeat scheduling in a calendar [http://i.imgur.com/y9Gn3wq.png],
>>>>>>> it will save real-estate within the dialog and it will be more easily
>>>>>>> readable for the user.
>>>>>> That's a good suggestion. Will do this.
>>>>>>
>>>>>>> - to my understanding, the New Snapshot functionality doesn't have to
>>>>>>> be recurrent; however, there isn't any way to "disable" the recurring
>>>>>>> aspect. Here are some suggestions to how this should be added:
>>>>>>> http://i.imgur.com/4j7hvRY.png
>>>>>> Once scheduled the only way to stop snapshot creation is to provide an
>>>>>> end date.
>>>>>>
>>>>>>> Option 3 is my personal favorite - it is the simplest, and is
>>>>>>> consistent
>>>>>>> with Calendear-scheduling UI. Option 1 is my least favorite, however it
>>>>>>> is consistent with e.g. the "Enable Power Management" UI within the
>>>>>>> "New
>>>>>>> Host" dialog.
>>>>>> Option-3 looks good to me as well. Should be doable I feel.
>>>>>>
>>>>>>> Snapshots -> Options:
>>>>>>>
>>>>>>> - I think that there are a couple of problematic issues with this
>>>>>>> dialog:
>>>>>>>
>>>>>>>       * the different functionality of this dialog when a Volume is
>>>>>>>       selected
>>>>>>> vs. when no Volume is selected may be unclear to the user.
>>>>>> Agree
>>>>>>
>>>>>>>       
>>>>>>>       * the fact that we can update Cluster-related parameters (which
>>>>>>> potentially affects *all* volumes in that Cluster) within a specific
>>>>>>> Volume-context dialog is a bit risky - and we don't have anything
>>>>>>> similar
>>>>>>> to that anywhere in the application today IIRC.
>>>>>>>
>>>>>>> my recommendations:
>>>>>>>
>>>>>>>       * have separate "Options - Cluster" and "Options - Volume"
>>>>>>>       actions;
>>>>>>> "Options - Cluster" should always be enabled.
>>>>>>> "Options - Volume" should be enabled only when a Volume is selected.
>>>>>> Accept
>>>>>>
>>>>>>>       * Seehttp://i.imgur.com/pfRpjrH.png  for my suggestion for
>>>>>>>       "Cluster
>>>>>>> Options" vs. "Volume Options". Note that from the "Volume Options"
>>>>>>> dialog, you may allow editing the Cluster Options by clicking on the
>>>>>>> link-button, which will either (a) open the "Cluster Options" dialog
>>>>>>> on top or (b) allow editing the Cluster Values inline within the
>>>>>>> already-open dialog - this should be accompanied with a clear note to
>>>>>>> the user that he is editing Cluster-related parameters from the current
>>>>>>> (Volume) context, which may affect *all* Volumes in that Cluster.
>>>>>>> Also note that in my suggestion, the user can conveniently see both the
>>>>>>> Volume values and the Cluster Values side-by-side at once, for
>>>>>>> reference.
>>>>>> Accept
>>>>>>
>>>>>>> Snapshots -> Schedule:
>>>>>>>
>>>>>>> - to my understanding, this should be very similar (or identical) to
>>>>>>> the
>>>>>>> New Snapshot functionality? if so, we may want to simply open the "New
>>>>>>> Snapshot" dialog focused on the "Schedule" side-section (rather than
>>>>>>> the
>>>>>>> 'General' side-section, maybe already pre-populated with some values in
>>>>>>> the 'General' side-section (which will still be editable by the user)
>>>>>>> and
>>>>>>> something already pre-selected in the (focused) "Schedule" section.
>>>>>>>
>>>>>>> please let me know whether you think these can/should be incorporated
>>>>>>> into the design, and/or if you have any comments or questions.
>>>>>> Accept. The snapshot create dialog itself can be used here.
>>>>>>
>>>>>>> thanks.
>>>>>>>
>>>>>>> ----
>>>>>>> Regards,
>>>>>>> Einav
>>>>>>>
>>>>>>> ----- Original Message -----
>>>>>>>> From: "Shubhendu Tripathi"<shtripat at redhat.com>
>>>>>>>> To:devel at linode01.ovirt.org,jhernand at redhat.com, "Michael
>>>>>>>> Pasternak"<mpastern at redhat.com>
>>>>>>>> Sent: Monday, November 10, 2014 1:52:40 AM
>>>>>>>> Subject: [ovirt-devel] Gluster Volume Snapshots - Feature review
>>>>>>>>
>>>>>>>> Hi All,
>>>>>>>>
>>>>>>>> Please help us to review the design of Gluster Volume Snapshots in
>>>>>>>> oVirt,
>>>>>>>>
>>>>>>>> Here are two design on wiki page
>>>>>>>>
>>>>>>>> General Feature Design
>>>>>>>> http://www.ovirt.org/Features/GlusterVolumeSnapshots
>>>>>>>>
>>>>>>>> Detailed Design
>>>>>>>> http://www.ovirt.org/Features/Design/GlusterVolumeSnapshots
>>>>>>>>
>>>>>>>> We target it in ovirt 3.6 release.
>>>>>>>>
>>>>>>>> Marked Juan/Michael specifically for REST review.
>>>>>>>>
>>>>>>>> Best Regards,
>>>>>>>> Shubhendu Tripathi
>>>>>>>> _______________________________________________
>>>>>>>> Devel mailing list
>>>>>>>> Devel at ovirt.org
>>>>>>>> http://lists.ovirt.org/mailman/listinfo/devel
>>>>>>>>
>>

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