Thank you for your replies, first...

Here my point is that clock synchronization is irrelevant in many (possibly all) current use cases, but is essential for others that are just potential. The user that hits such a use case is unable to implement clock synchronization in the cloud (as far as I know), so he/she may be happy to pay an extra to have a clock within 1 second from UTC on certain VMs, and add a new use case. The simplest idea that comes to my mind (maybe wrong) is to provide clock specs through a mixin.

The boundary of "what is subject to a SLA" is subtle. But a feature included in a SLA is somewhat static, and does not (necessarily) go through the user interface. Clock synchronization is a switch you can set on/off, and that requires specific actions on the side of the IaaS provider. 

I would be happy to know if anybody experienced the case where a lack of synchronization in the cloud was a problem. If only  I'd know what PDC is ...

Augusto

2011/9/20 Edmonds, AndrewX <andrewx.edmonds@intel.com>
I think Alex hits this on the nail by noting "as part of the [...] SLA",
which would be then related to the provisioning of the compute resources but
not necessarily to the current OCCI spec where consideration for SLAs is not
(yet?) present.

Andy

-----Original Message-----
From: alexander.papaspyrou@tu-dortmund.de
[mailto:alexander.papaspyrou@tu-dortmund.de]
Sent: Tuesday, September 20, 2011 11:27 AM
To: Edmonds, AndrewX
Cc: augusto.ciuffoletti@gmail.com; occi-wg@ogf.org
Subject: Re: [occi-wg] About clock synchronization in the cloud

>From my point of view, this is out of scope. Getting the hardware clock
"right" is a job that has been solved on the operating system level, using
Distributed Systems protocols like NTP.

I agree that, for many services, exact time is crucial (try to deliver a PDC
with a broken clock.), but this would be either something that

a) may be part of an operating system template mechanism, where you know
that such basic services are available or
b) is ensured through quality of service parameters (as part of the contract
or SLA between consumer and provider)

Making it an attribute seems to be the better of the two options for OCCI,
but it still doesn't make that much sense -- what does an attribute on the
clock (which way ever this attribute is structured) tell me other than that
the clock is there and in sync (with a drift of x and skew of y) at any
time, and why would I want to discover this information via the OCCI
interface?

Just my two cents.
-Alexander

Am 19.09.2011 um 22:39 schrieb Edmonds, AndrewX:

> Sounds like a good discussion topic! It might be a little out of scope for
OCCI, but who knows where the discussion might lead to or what it might
highlight.
>
> Andy
>
> From: occi-wg-bounces@ogf.org [mailto:occi-wg-bounces@ogf.org] On
> Behalf Of Augusto Ciuffoletti
> Sent: Monday, September 19, 2011 9:33 AM
> To: occi-wg@ogf.org
> Subject: [occi-wg] About clock synchronization in the cloud
>
> Dear all,
>
> I was wondering whether the features of the system clock of a virtual
instance (compute or storage) may be of interest for the user. I wrote down
500 words on the topic (see Google doc below), and I'd be pleased to know
your opinions, taking advantage of the intense "brain storm" during next
OGF.
>
> https://docs.google.com/document/pub?id=1imafqyrVscdTbdfjngJ4Xfbg1DIoe
> bdyzyQSPmDgOCY
>
> Bye
>
> Augusto
>
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--
Alexander Papaspyrou
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