On 09/16/2011 02:24 PM, Andrea Cristofori wrote:
Hi John,
Some short and personal comments on what you wrote:
1) Indeed I think that StAR has its own life but eventually I feel that single definition of UR is preferable. My understanding is that EMI needed something soon so they defined this type of UR for storage. OGF, on the other hand, could produce a new version of UR that includes many (or all if there is agreement) attributes of StAR. Those attribute could be then left optional as well as those for CPU or other resources and depending on the needs different attribute can be used.
Hi Andrea, I think we agree on this point. It's really good that the EMI guys have got StAR to the point that they have and seeing some real life use of a storage accounting record will provide us with some good feedback if we consider extending the OGF UR. It's also generating more discussion and we can learn a lot from StAR.
11) There has been some discussion on that and I also feel that this ValidDuration is artificial. What I suggested was something like having a TimeDuration that represent the time the storage has been used. This leads to differences in the way the used space is reported: if for example no UR is produced before the ValidDuration you end up with a hole in the accounting. With the other system you might have an occupation of the storage that is constant. This could happen if, for example, the storage was offline. The result is that with ValidDuration seems that no storage was used when, in fact, the file(s) were still there (even if not accessible).
I fear that the only way a true TimeDuration could be achieved would be with changes in the storage engines them selves. Currently we're just living with snapshots and then starting to do our best. We have snapshots with give bytes but we need byteseconds (or something) IMHO. But again this currently isn't possible without some guessing/assumptions. As I said my idea case would be each file is somehow registered in an accounting database on storage and it's deletion data is also registered. Thus something like the qacct tool could be used which would summarize storage usage over a time period. I think the storage solution providers could be asked if this is at all possible or if (due to millions of files) this is going to get far too large to manage. I look fwd to seeing any discussion on this at the OGF.
We will try to keep you and all the people on the UR-WG mailing list that won't be able to be in Lyon with a report of the discussion. See you soon maybe to next OGF.
many thanks cheers johnk
Andrea
On 09/16/2011 12:42 PM, john alan kennedy wrote:
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 us.
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 document. 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 attributes"
"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?
e.g.
<SubDirs> <SubDir>/atlas/data/2011/January</SubDir> <SubDir>/atlas/data/2011/February</SubDir> <SubDir>/atlas/data/2011/March</SubDir> <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 ignored.
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
"GroupAttribute"
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
"ValidDuration"
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 validity?).
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.
Cheers Johnk
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
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