[UR-WG] Call for input on storage accounting record

john alan kennedy jkennedy at rzg.mpg.de
Fri Sep 16 05:42:08 CDT 2011

Hi Jon,

I'm sorry to say that I won't be able to attend the OGF meeting. But I 
obviously look forward to seeing the results of the discussions there.

I have read through the Doc and do have some comments. (I'm obviously 
missing a lot since I have not attended an OGF for a while but here goes)

General Comments:

1) w.r.t usage the ogf UR.
I don't think this is a new comment

If possible it would be ideal to ensure that the UR for storage and the 
UR for compute can somehow be coupled together.
This could either mean extending the UR so it could include both storage 
and compute or ensuring that both records could be identified as having 
the same logical origin (site and our group) during the same time period.

This may be achievable in the process of transforming accounting records 
into billing records. So you may be able to argue it isn't needed in the 
UR but is part of the machinery for processing the URs into billing 
records for funding.

I just feel that if possible we should ensure that both compute and 
storage URs can be correctly associated and processed together.

Anyway the StAR may be seen as stand alone and as a practical forerunner 
which could help show the way to defining a more global UR.

2) Section 2.1.1

Although I agree with you that storage accounting is more problematic 
that cpu accounting I still have the feeling that this is partially due 
to the storage systems themselves.

I feel you outline why things are difficult and then with StAR you go 
about defining the best way to do storage accounting with what we have 
at the moment.

On our batch system (sge) I have qstat which gives me a view of current 
resource usage and I have qacct which gives me the ability to get a 
summarised usage over a time period based on user/group.

At some point I'd like to see if the storage engine providers feel that 
this type of functionality could be added to their systems.

That would make the job of providing storage accounting much simpler for 

It may be that the providers say it's simply too much.

Specific Comments:

1) Section 2.1.2

"Identity: Describes the person or group.... " should this be and/or can 
you have person,person+group,group?

2) Section 2.1.3

Allowing additional records: I know some people are against such 
practices since allowing this can break standards (people put whatever 
they want in and things start to get incompatible ... I guess it's your 
design choice and it's up to you)

"This makes it possible to automatically remove user and group information"

I'd suggest:

"This makes it possible to automatically remove user and group 
information, a practice which may be needed for anonymization purposes"

so I know why people may need to do this.

3) Section 2.2.2

"The specifications that are made in the following are based on a 
context that the reader needs to comprehend."

I assume you mean that the following two specifications/Definitions "A 
Storage Resource" and "Storage Accounting" are used in this document and 
are important for it's understanding.

I think this needs some re-wording for clarity.

4) Section 2.4.1

For the opening sentence: from the original UR doc I like the sentence 
"The UsageRecord element encapsulates a single Usage Record" And I don't 
mind stealing.

The term "property" is used here and at numerous other places in the 
I understand that this is since it's a property of your record, however, 
I would suggest using the term "element" since you have already defined 
the XML nature of the record and I think this would make things a little 
easier to understand.

"top container property" -> "top level element of the storage record format"

(maybe keeping the "container" is ok? "container element" ?)

5) Section 2.4.3

If you wish to follow the "property -> element" suggestion.

"The field has two attributes" -> "The RecodrIdentity element has two 

"The field is similar to the field with the same name in the Usage 
Record standard"  - do you need to say this?

Saying "similar" makes me start to think,"can't be used with UR", "why 
not the same?"

You explicitly stated earlier that you've taken steps to make things 
similar but had problems so I am not sure if you need to say this here.

6) Section 2.4.4

"The storage system value SHOULD be constructed in such a way that it 
globally identifies the storage system"

I was originally not sure if MUST would be better but I assume you have 
worries about the ability of people to enforce this?

Also "globally" I think this should be accompanied with a "uniquely".

I believe here you wish to make the recommendation that people use a 
unique global name?

"globally" is not "uniquely" but I think that is what you want and I 
think you use the term "global" to mean this in a few places.
I'd suggest skimming the doc and adding unique where you mean this to 
make things more clear.

7) Section 2.4.5

"StorageShare" why "Share"? This makes me think of my share of the pie 
or fair share and it's a touch misleading.
I'd suggest some thought about an alternative name, but I don't have a 
good suggestion "StorageSubSystem"?

8) Section 2.4.9

"DirectoryPath" We all tend to think in unix terms and at least the 
storage systems that I have met have a tendency to expose their content 
in these terms as well but is it really a directory path and not a 
namespace path. I fear there's some storage system out there that I 
didn't meet yet that doesn't have a /abc/def/file format for displaying 
the data collections.

It's an optional element so this may be a moot point.

Either way I think it would be good to include a term such as "logical 
namespace" within your description to clarify that it's not physical but 
the storage systems logical namespace that you are referring to.

w.r.t "the record should account for all usage in the directory and only 
that directory".

do you really mean "only that dir"?

a) would this not limit it's usefulness?

If I have /atlas/data/2011 and I want a record that contains atlas 2011 
data usage I would need to sum through all subdirs

Is this what you really mean? (dir+subdirs)

b) would you allow a container that has a list of all subdirs?



Would you consider allowing regexp in these definition (is this possible?)

c) If you do mean "dir+subdirs" then any links which are made within 
this tree could break you out and cause problems (wrong/double 
accounting etc) so it would be good to be explicit that these should be 

9) Section 2.4.11

"MUST be under the SubjectIdentity" if you take my xml elements comment 
from before (my 3rd comment) then this could be "MUST be a child element 
of the SubjectIdentity element"

This and similar things happen a few time throughout the document, in 
2.4.12-2.4.13 etc... skim and change if you like.

10) Section 2.4.15


If you do use the XML context (my 3rd comment) then using the term 
"Attribute" here may cause a little confusion.

So re-naming may help here (GroupProperty ?)

Additionally since you say "MUST be under the SubjectIdentity" I would ask:

Should this be a child element of "Group" or a real XML attribute? As 
you say Group needs to exist for GroupAttribute to exist and so this 
would make things
easier if you ask me (more strongly defined).

These may be seen as XML style questions and looking up some XML best 
practices (or asking someone who is an XML guru) may help clear this point.

w.r.t. "The GroupAttribute property can be repeated", are there any 
possible restrictions here? Could people have several roles/subgroups 
and would this then lead to possible confusion in the interpretation of 
the record?

I think youi may be able to argue that you just present the information 
in the record and it's up to others to decide how to interpret it (w.r.t 
billing etc).

11) Section 2.4.17


To me this feels a bit artificial. I am not sure if it's needed, how 
it's justified (is everyone free to make a guess at the period of 

If it's there to enable people to change accounting into billing then 
I'd also suggest this is a policy issue to be discussed between the 
sites providing the storage and those using the storage.

It may be seen as a necessary measure by you but I feel a little unsure.

If the records are indeed provided on a more frequent basis that the 
duration time then it's invalidated and not needed.

The records themselves are snapshots by nature and the interpretation of 
what happens in between them is open IMHO.
Even if you add a validity duration it has no meaning that the situation 
wasn't completely different on the storage itself.

I think that the records are only really invalidated by a true measure 
of the system state at a later time.

Any policy decisions regarding this can be made and applied externally 
to the StAR itself.

I think this partially goes back to my 2nd General comment. We can 
currently only get snapshots of the system state and we may need to live 
with defining storage accounting based on this.

12) Section 4.1.1

I guess you already saw this but there is an "Error: Reference source 
not found" when you refer to Figure1.

I would like to re-read the appendix just to make sure I understand what 
you're saying there and that it's clear enough to me.
Maybe I read it too fast the first time but I was a little confused with 
some points.

There are a few places where I would have liked to suggest some slight 
modification to improve the English a little.
However I didn't think that was the real aim of your request for comments.
My English isn't perfect but I'd be willing to help out a little here if 
you like.

I also want to again I'm sorry i won't be attending the OGF. I know 
comments to docs like this are welcome but I also know I'm missing a lot 
of the discussion and so some comments may be unneeded/outdated.

I hope you all enjoy Lyon.


On 09/08/2011 01:44 PM, Jon Kerr Nilsen wrote:
> Hi all,
> OGF 33 is approaching and there will be a working session for UR-WG. As you might be aware of, EMI has created a description for a storage accounting record (StAR) to be proposed as an OGF standard (or as input to a new usage record). I would therefor like to ask for some last comments on the StAR document, to be found here:
> http://cdsweb.cern.ch/record/1352472?ln=en
> I'd need input to it within September 16 to be able to discuss it at OGF.
> thanks,
> Jon
> UR-WG co-chair
> --
>    ur-wg mailing list
>    ur-wg at ogf.org
>    http://www.ogf.org/mailman/listinfo/ur-wg

|Dr. John Alan Kennedy          Rechenzentrum Garching (RZG) |
|Mail:  jkennedy at rzg.mpg.de     Boltzmannstrasse 2           |
|Phone: +49 89 3299 2694        85748 Garching               |
|Fax:   +49 89 3299 1301                                     |

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