Open Stack

On Mon, Feb 28, 2011 at 6:49 PM, Brian Lamar <brian.lamar at rackspace.com> wrote:
> Just because I can't help but asking, when does data specified during instance creation stop being data and start being metadata? While it seems like a silly question I'm wrestling with the idea of metadata actually *doing* something.

I've brought this up as well. Metadata is data about the data's
structure (or the data's container). Unfortunately, the CS API spec
uses metadata to refer to free-form *properties* or *attributes* of
the instance, and the decision was made to stick to what the API spec
said to avoid confusion (didn't exactly work out that way, I know ;) )

> I was under the (perhaps false) impression that metadata could be added by end-users and was a way to describe associated data about an object which didn't impact it's being. For example, we don't set the image type with metadata, instances are created by providing an image type. Perhaps the two aren't analogous because if "openstack:near" changes the instance would migrate to another location? Or if "volume-000001" was moved, does the instance move too?

The things that have so far been described as "metadata" are not
metadata at all, nor are they "metacontent" (see below). They are
merely attributes of the end-user request to allocate some resource.

-jay

for those of a like-minded curiosity about these things. From the
wikipedia article on this same subject:

"The term Metadata is an ambiguous term which is used for two
fundamentally different concepts (Types). Although a trite expression
"data about data" is often used, it does not apply to both in the same
way. Structural metadata, the design and specification of data
structures, cannot be about data, because at design time the
application contains no data. In this case the correct description
would be "data about the containers of data". Descriptive metadata on
the other hand, is about individual instances of application data, the
data content. In this case, a useful description (resulting in a
disambiguating neologism) would be "data about data contents" or
"content about content" thus Metacontent. Descriptive, Guide and the
NISO concept of Administrative metadata are all subtypes of
metacontent."