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From John Burwell <>
Subject Re: S3-backed Secondary Storage Enhancement
Date Thu, 13 Dec 2012 18:16:59 GMT

There don't appear to have been any updates to the review since 7 Dec 2012.  What the status
of getting further review?

In addition to submitting the review request, I have also opened a enhancement ticket in JIRA
[1] and created a design document in the wiki [2].  How do we go about getting this feature
placed on the 4.1.0 roadmap [3]?

Thanks for your help,


On Dec 10, 2012, at 1:29 PM, Chip Childers <> wrote:

> On Mon, Dec 3, 2012 at 10:25 AM, John Burwell <> wrote:
>> Chiradeep,
>> Please see my responses in-line below.
>> Thanks,
>> -John
>> On Nov 20, 2012, at 9:33 PM, Chiradeep Vittal <>
>>> I must give kudos on the document
>>> (
>>> +Storage ). Quite complete
>>> If the intent is to make immutable assets (templates etc) visible across
>>> all zones:
>>> 1. Does the template_zone_ref table still make sense? Is it automatically
>>> updated?
>> Yes, the template_zone_ref table is still required.  Templates and ISOs must be attached
to a zone.  From my understanding of the system design, removing this requirement would require
a fundamental data model/architectural change.  Therefore, cross zone templates are supported
by creating a row in the template_zone_ref table associating the template to the zone.  These
propigation operations are performed upon template and zone creation.  This behavior pre-dates
this patch.  This patch automates the operation of propagating the data across zones.
>> I have updated the data model section of the design document to describe the data
flow and role of each table.
>>> 2. If I request a vm deployment from a template in a zone that has not yet
>>> sync'ed, what is the behavior?
>> The short answer is that S3 download behaves similarly to Swift downloads.  Templates
and ISOs are downloaded from S3 to NFS on-demand.  When a template is not found in the NFS
volume, the system will attempt to downloaded it from S3.  As noted in the design download,
this on-demand behavior may create a slight lag when a template is initially accessed in a
zone dependent on the available bandwidth between the SSVM and the S3-compatible store.
>>> 3. If I add a zone is the sync automatic to the new zone
>> Yes, per the template propagation and on-demand download behaviors described above,
templates and ISOs will automatically be available in a newly created zones.
>> I explained this process in the Architecture/Design section, and have updated it
based on on my response here.  Please let me know if it is needs further clarification.
>>> On 11/18/12 10:51 PM, "John Burwell" <> wrote:
>>>> All,
>>>> I have submitted the initial revision of a patch to support S3 backing
>>>> NFS secondary storage (  I have
>>>> opened ticket CLOUDSTACK-509 to track the testing and delivery of the
>>>> enhancement.  I have also created a design document in the wiki roughly
>>>> following design document template.  Since I am not a committer, it did
>>>> not seem appropriate for me to add a reference from the roadmap to the
>>>> ticket.
>>>> In its current state, I have tested the single zone template and ISO
>>>> functionality on devcloud.  I am working to configure a multi-zone
>>>> integration testing environment to complete all test scenarios outlined
>>>> in the design document.  My plan is to refine the arch per community
>>>> patch concurrently with the completion of integration testing and bug
>>>> squashing.
>>>> I look forward to your feedback,
>>>> -John
> Edison, Chiradeep, Rohit -
> Can you guys spend some time on the latest proposed patch [1] to see
> if the outstanding issues / questions have been resolved?  If it looks
> good, we should get the changes committed to the master branch.  I'd
> like to get this feature into the 4.1.0-incubating release.
> -chip
> [1]

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