[ogsa-naming-wg] WS-Directory critique

[Osamu Tatebe]

I am looking through the WS-Directory Specification.  

https://forge.gridforum.org/projects/ogsa-naming-wg/document/draft-wsdir-rec-doc-v1/en/1
https://forge.gridforum.org/projects/ogsa-naming-wg/document/draft-wsdir-wsrf-rendering-doc-v1/en/1

Here are some comments for now:

1. Referral, Logical Reference, and Endpoint Reference

Each entry of WS-Directory has entry-name (string) and entry-reference
(EPR).  How to identify a service that is referenced by the
entry-reference?  At least, we would like to identify a referral (EPR
to a WS-Directory), a logical reference (EPR to a resolver service),
or an endpoint reference (EPR to any endpoint reference service).
These entries are quite typical cases in Grid file system.  Otherwise,
there is no way to interpret the entry-referene by a client.

2. Access control list (ACL)

We, GFS-WG, would like to introduce access control mechanism in
hierarchical naming space just like directory-based access control in
ordinal file system.  The access control can be on a user basis and on
a group basis for each file and directory.  It is not possible to
access even namespace itself if it is under a directory that is not
allowed to be accessed.  Moreover, the access control list can be
modified by the owner, or permitted users.  How can this mechanism be
introduced in WS-Directory?

3. Metadata

WS-Directory does not include any metadata in each entry except
entry-reference.  On the other hand, modification time of a directory is
useful to know whether a client copy of entries is up-to-date or not.

For Grid file system, we would like to attach several metadata
additionally in hierarchical namespace (directory structure), which
includes times, size, checksum, and possibly ACL.  We would really
like to have extensibility interface to add metadata.

4. Iterator

When we have tens of thousands of entries, or millions of entries in a
directory, listing entries takes very long time or even causes
OutOfMemoryError.  For example, see the slide of "Performance
evaluation of Virtual Filesystem Directory Service (VFDS)" at GGF12
GFS-WG session.

http://forge.gridforum.org/projects/gfs-wg/document/Performance_evaluation_of_VFDS/en/1

That is why we feel iterator or enumeration is indispensable for
listing entries.

5. Remove entries using wildcard

WS-Directory permits removal of entries using wildcard.  What happens
if some entries among specified cannot be removed?

Thanks,
Osamu

---
Osamu Tatebe, Ph.D.   Tel: +81-29-861-5844  FAX: +81-29-862-6601
Grid Technology Research Center,
National Institute of Advanced Industrial Science and Technology (AIST)
AIST Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 3058568 JAPAN
E-mail: o.tatebe at aist.go.jp     http://phase.hpcc.jp/people/tatebe/