[ogsa-naming-wg] Re: GGF/OGSA standards for hierarchical namespaces

[Gregory Newby]

It's not too late to schedule time at GGF17 for a cross-group
meeting.  (Well, it's a little too late...but not completely
unreasonable to attempt.)
  -- Greg


On Tue, Mar 28, 2006 at 11:17:54AM -0800, Allen Luniewski wrote:
> Chris,
> 
> Thanks for the very thoughtful note!  A few comments.
> 
> I agree with you that the current situation is, to put it mildly, not 
> acceptable.  We need to move to a position where the community agrees on a 
> single means for creating a hierarchy of pointers to resources (a 
> directory structure in Unix-speak).  Clearly one aspect of this is that 
> RNS and WS-Directory need to reconciled into a single proposal. Resolution 
> sooner rather than later is clearly in the best interests of the various 
> WGs who depend upon directories (including OGSA Data which I share 
> responsibility for).
> 
> You mention a couple of specific technical issues.  A few comments on 
> those:
>         1. I go back and forth on attributes in the directory system. 
> Since these are almost certainly cached from the resources, today I am 
> inclined to say that
>                 attributes should not be part of the directory system. Ask 
> me tomorrow, and I may have the other answer :-)  But today, I would leave 
> them out
>                 of the base specification for simplicity but consider an 
> extension that included attributes if that were felt to be vital.
>         2. Dave Berry's suggestion to separate out the iterator component 
> is a good one.  There are going to be many places in the overall grid 
> standards
>                 effort where an iterator-like structure will be needed. 
> Standardizing this seems like a proper goal for GGF.  If that is accepted 
> then using it
>                 in a directory service seems quite natural.
> 
> As for moving forward, I think that we need to see how this thread plays 
> out.  My instincts, however, are that getting the interested parties in a 
> room for a few hours would be the most effective way to drive this to an 
> early resolution.
> 
> Allen Luniewski
> IBM Information Management Division
> San Jose, California
> 
> 
> 
> 
> Christopher Jordan <ctjordan at sdsc.edu> 
> 03/27/2006 05:28 PM
> 
> To
> Osamu Tatebe <o.tatebe at aist.go.jp>
> cc
> Arun Jagatheesan <arun at sdsc.edu>, Manuel Pereira 
> <mpereira at almaden.ibm.com>, Andrew Grimshaw <grimshaw at cs.virginia.edu>, 
> Mark Morgan <mmm2a at virginia.edu>, Dave Berry <daveb at nesc.ac.uk>, Allen 
> Luniewski <luniew at almaden.ibm.com>, Christopher Jordan 
> <ctjordan at sdsc.edu>, Hiro Kishimoto <hiro.kishimoto at jp.fujitsu.com>, Ian 
> Foster <foster at mcs.anl.gov>, Gregory Newby <newby at arsc.edu>, 
> gfs-wg at ggf.org, ogsa-naming-wg at ggf.org
> Subject
> GGF/OGSA standards for hierarchical namespaces
> 
> 
> 
> 
> 
> 
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> 
> All,
> 
> Forgive the wide distribution on this e-mail, but this issue seems to 
> be to be both extraordinarily important to the future of GGF/OGSA 
> standards efforts and also in a state of either limbo or paralysis. 
> The topic I'm addressing here, both in my capacity as the secretary 
> of GFS-WG and as a generally interested participant on a few 
> different GGF working groups, is the question of adopting a single, 
> possibly minimal, standard for creating hierarchically organized 
> collections of pointers (WS-Names? GSR/GSHs, to date myself?) to 
> "resources", where the term "resource" could denote a service 
> providing access to a collection of files, computational resources, 
> or database records (that's a non-exclusive list), and where some 
> items in the hierarchy could actually represent directory-like 
> structures, i.e. containers for other collections of resources.
> 
> The way I got involved in this discussion through the Grid File 
> Systems-WG, which at the time was bringing the RNS specification 
> forward for final approval as a GFD. Subsequently, there have been 
> numerous discussions outside of the GFS-WG context about the 
> suitability of the RNS standard for more general applications, as 
> well as the (perceived) complexity of the standard as a barrier to 
> entry. There have also been alternative directory construction 
> standards proposed by members of the OGSA-Naming-WG.
> 
> The following are the activities/proposals I know of:
> 
> RNS: I know the GGF editors have returned the final(?) RNS draft to 
> GFS-WG, with the suggestion that it is too specific to filesystem 
> needs, and the suggestion that it either be limited in scope to GFS 
> applications only (a non-optimal solution for obvious reasons) or 
> that the authors work with the OGSA-Naming people to help develop a 
> universal standard for hierarchical resource namespaces. If we are to 
> move forward with RNS, one of these options will clearly be a 
> necessity, given the points Greg Newby made in his responses on 
> behalf of the GFSG.
> 
> WS-Directory: This is the hierarchical namespace standard developed 
> at UVa in response to their difficulty in implementing the 
> complexities and ambiguities in RNS. I like the simplicity of WS- 
> Directory, however it seems to be missing significant requirements 
> for general use such as attributes, both attributed which should be 
> required such as time-to-live, and the ability to add extensibility 
> attributes such as resource type, QoS, etc. This ability to add 
> arbitrary attributes is present in RNS but it still lacks some 
> obviously fundamental required attributes.
> 
> Finally, Dave Berry sent an e-mail immediately after GGF16 in which 
> he mentioned the suggestion that we separate this functionality into 
> two logical functions, and therefore standards - a Directory 
> Interface and an Iterator interface, in which Directory interfaces 
> were essentially just pointers to Iterators, which would be 
> standardized. However, there would be no restriction that a Directory 
> point to a particular type of iterator interface. One point I wasn't 
> clear on from the e-mail was whether an entry in an interator could 
> be another directory, although I suspect it can.
> 
> This short list is what I've got within easy reach. As I said 
> previously, I believe this is an important issue to resolve quickly, 
> and I'm sending this note in the hopes of initiating the conversation 
> among as many of the relevant parties as I can. Please feel free to 
> forward at will, respond with agreement, anger, or even unconcealed 
> rage.
> 
> Possible ways forward would be for us to have a conference call (GFS- 
> WG meets rarely, and we could quite easily give up our call for a 
> more focused discussion of these issues), an extended e-mail 
> discussion, or a meeting at the next GGF (assuming we get a chance).
> 
> Let me know how you feel about the options presented above, or feel 
> free to propose new ones if you like. The important thing is that we 
> begin to gain momentum, and then keep it going forward.
> 
> Thanks.
> 
> N.B. For anyone who may have missed any of the discussions reference 
> above, please let me know and I'll be happy to forward them to you 
> from my archives.
> 
> - ----------------------------------------------------
> Chris Jordan
> HPC Systems Engineer
> High End Computing Systems Group
> San Diego Supercomputer Center
> ctjordan at sdsc.edu
> 858.534.8347
> 
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Dr. Gregory Newby, Chief Scientist (Acting), Arctic Region Supercomputing Ctr
Univ of Alaska Fairbanks-909 Koyukuk Dr-PO Box 756020-Fairbanks-AK 99775-6020
e: newby AT arsc.edu v: 907-450-8663 f: 907-450-8603 w: www.arsc.edu/~newby