[glue-wg] New attribute for GLUE 2.1: StorageShare.ViewID

[Paul Millar]

On 26/09/14 11:12, stephen.burke at stfc.ac.uk wrote:
> Paul Millar [mailto:paul.millar at desy.de] said:
>> The Storage Shares representing physical hardware were intended
>> for "installed capacity" calculations.
>
> As far as I remember the Capacity objects have a Type attribute which
> is supposed to be e.g. "online" for the standard uses and
> "installedonline" for installed capacity publication (and since it's
> an enumerated type, other values can be defined). Is it not possible
> to get the effect you want using that?

The short answer: no.

The longer answer: yes.

The slightly longer answer still:

No, because these are different concepts: SSC.Type is about what kind of 
storage you are accounting for, not whether or not two Storage Shares 
overlap.

The more accurate answer:

Yes, by having explicit knowledge of how the WLCG clients behave, I can 
construct information such that one set of clients see one thing and the 
other set of clients see something else.

Specifically, I "know" (suspect) that WLCG clients querying about SRM 
reservations are interested in StorageShareCapacity where Type=ONLINE. 
I also "know" (strongly suspect) that those clients doing accounting are 
interested in Type=INSTALLEDONLINE.

Therefore, I can publish SRM shares with only SSCs with Type=ONLINE and 
Physical shares with only SSCs with Type=INSTALLEDONLINE.

Magic! Problem solved!

But the solution is fragile, requires undocumented knowledge, and 
excludes other clients from working.  What if ATLAS wants to query 
INSTALLEDONLINE values for their space reservations?

Also, this is the kind of name-convention-style brokenness we wanted to 
get away from in the transition from GLUE 1.3 to GLUE 2.0.

I say lets fix the with GLUE 2.1, since we are making another release.

(A ViewID *may* even be useful outside of the Storage model.)

As usual, my 2 Euro-cents worth ;-)

Paul.