**SciDAC DataGrid Middleware**

**A High-Performance Data Grid Toolkit:**

**Enabling Technology for Wide Area Data-Intensive Applications**

**Quarterly Report July 2002 thru September 2002**

[**Accomplishments this Quarter**:]{.underline}

***Completed first design iteration on Globus XIO (extensible IO
system)***

Globus XIO will provide a protocol pluggable read/write/open/close
interface for IO. This will allow an application written with XIO to
easily change the underlying transport protocol. The new GridFTP server
will be built using XIO and this will allow us to easily provide a
non-TCP GridFTP implementation, one of our project deliverables. We will
also provide a GridFTP driver for XIO allowing other application to more
easily add GridFTP support.

***Participated in IGrid 2002***

Collaborated with Caltech on a demonstration involving analysis of
physics data on the show floor in Amsterdam that was stored in Chicago.
Striped GridFTP was used to move the requested data sets via StarLight
over a trans-Atlantic 10 Gigabit Ethernet link. The performance was
significantly less than expected (about 1 Gbs). Investigations of the
root cause of the problem are underway and a paper describing this is
underway.

***Transport Activities in GGF***

The GridFTP working group is nearing completion of the specification for
V1.0. We project having the final version submitted prior to GGF7. Also
held a BOF proposing the formation of a research group on data transport
issues. There was fair attendance, but a lack of people willing to do
volunteer to do concrete work. We are continuing to pursue formation of
this group.

***Technical Meeting to discuss HPSS / GridFTP integration held***

IBM / HPSS has committed to using GridFTP as the interface to HPSS. A
technical meeting was held to discuss possible issues, interaction
logistics and timelines. We are targeting release 6.2 of HPSS in early
to mid 2004 for production release of HPSS with GridFTP as its access
protocol.

***Continued development and testing of the Replica Location Service***

During this quarter, we continued our development and testing of the
Replica Location Service. Features added to the RLS this quarter
include: 1) Improved packaging and documentation 2) Implementation of
bloom filter compression 3) Implementation of a Java version of the
client API that wraps the existing C client; 4) Implementation of a
gridmap file for the RLS servers that supports GSI authentication.

***Deployment of RLS into collaborator Testbeds***

The Earth Systems Grid project has deployed a Local Replica Catalog as
part of their testbed. The ESG LRC contains several thousand mappings of
file replicas from the PCM and CCSM climate data sets. The RLS is also
being deployed throughout the extensive testbed of the European DataGrid
project. We continue our testing efforts with Work Package 2 of the EDG
project, and the two projects plan to participate jointly in a demo at
the upcoming SC2002 conference.

***New Initiative to Turn the Replica Location Service into an Open Grid
Services Architecture Service***

In August and September 2002, we began discussions internally and with
IBM on the possibility of turning the Replica Location Service into a
Grid Service compatible with the Grid Services Specification of the Open
Grid Services Infrastructure working group of the Global Grid Forum.

A two-day meeting that focused on opportunities for collaboration
between Globus and IBM on data grid architectures and services was held
at USC Information Sciences Institute on 12-13 September 2002.

***Metadata Catalog Service Prototype Completed and Used in Earth
Systems Grid***

During this quarter, we completed implementation of a prototype of the
Metadata Catalog Service. The MCS service maintains metadata that
describes the contents of logical files in a data grid. The Metadata
Catalog Service (MCS) allows users to query based on attributes of data
rather than data names. In addition, the MCS provides management of
logical collections and logical views of files. Our prototype uses a web
server front end and a relational database back-end to implement the
schema described in the Metadata Catalog design document that was
produced last quarter. The original MCS design was expanded in the
current quarter to provide better support for XML metadata, including
shredding the data and storing it efficiently in relational tables as
well as providing the capability to reconstruct the original XML files.
The prototype implementation includes a Java client API for loading and
querying the MCS. An MCS has been incorporated into the Earth Systems
Grid testbed and currently holds metadata for the PCM and CCSM climate
models. The ESG MCS will be used as a central part of the ESG prototype
for SC2002.

***Grid Reliability Workshop at USC Information Sciences Institute***

A two-day workshop on reliability issues for grids was held at USC
Information Sciences Institute on 10-11 July 2002. Approximately 15
people from several groups including Globus, Condor, San Diego
Supercomputing Center and Fermi Lab attended the meeting and
participated in discussions on grid reliability issues and approaches
for improving reliability.

***Developed "migratory file services" for scientific applications.***

This system performs caching and some prefetching for applications
running in a remote environment. Academic paper in progress.

***Continued maintenance and development of the NeST grid storage
appliance.***

More accounting and maintenance features added as well as enhanced
support for migratory users.

> ***Additionally, the following task were also accomplished by the
> Condor team:***

-   Applied the fault-tolerant shell
    (http://www.cs.wisc.edu/\~thain/research/ftsh) to solve reliability
    problems in the CMS distributed terascale facility (DTF) production
    run.

-   Developed the "sparse file" abstraction for reliable I/O
    interactions in a distributed system. Academic paper in progress.

-   Hardened the Pluggable File System
    (http://www.cs.wisc.edu/condor/pfs) according to user needs.

-   Improved error-handling facilities and documented them in a
    technical report in progress.

-   Hardened the Java I/O support in Condor in order to deal with the
    vagaries of various Java implementations. Now in production use at
    several sites.

-   Modified and re-deployed the FTP-Lite package
    (http://www.cs.wisc.edu/ftp_lite) to accommodate changing FTP
    protocols.

**Plans for next quarter**

***Continued development and testing of Replica Location Service***

We plan to continue development and testing of the RLS in the coming
quarter. However, to some extent, the current set of features has frozen
until we get additional feedback from our user community about whether
additional functionality is required, so our efforts will be focused
more on testing and debugging the code. Planned development for the
coming quarter includes making the RLS GT3 security compatible, which
requires that the RLS accept the new GSI certificates that will be
developed as part of the Globus Toolkit version 3.

***Widespread deployment of Replica Location Services\
***We will focus on widespread deployment of RLS in the coming quarter.
We will deploy a fairly large RLS testbed as part of a demonstration of
RLS for the SC2002 conference. This testbed will include approximately
twelve replica location index nodes and a larger number of local replica
catalogs. Development for the testbed includes creating specialized
information providers for the MDS information system to reflect the
state of RLS catalogs in the testbed.

In addition to the RLS testbed, we will continue to work with other
applications, including ESG, LIGO and PPDG, on deploying RLS systems for
their testbeds.

***Development of Replica Location Grid Service Specification and GGF
Working Group***

In the coming quarter, we plan to develop a first draft of a
specification document for an Open Grid Services Architecture Replica
Location Service. This draft specification will be developed under a
proposed OGSI Data Replication working group of the Global Grid Forum.

***Continued development of Metadata Catalog Service***

We will continue developing and experimenting with the MCS. We plan to
spend some time in the next quarter evaluating the preferred back-end
technology for the MCS. In particular, we will evaluate whether the
current relational back-end should be retained or replaced with a native
XML database back-end. In addition, we will work on extending and
generalizing the current Java API to support general XML queries. We
will continue working with applications such as ESG and LIGO that are
actively deploying the MCS and evaluating its functionality and
performance.

Proof of Concept implementation of Globus XIO

We will implement a rough proof of concept version of XIO to evaluate
our design. It is likely we will then iterate the design to refine it
based on our experience. We also intend to release this refined design
to a group of \"trusted friends\" for review and comment.

Investigate Performance Issues Discovered at IGrid 2002

We intend to keep the 10 GigE trans-Atlantic link operational for
further testing and investigation in to what is needed in order to
utilize high bandwidth, high latency links. Hopefully, we will be able
to utilize this knowledge to obtain better performance during the
Bandwidth challenge at SC2002.

**Papers Published or in Progress**

John Bent, Andrea Arpaci-Dusseau, Remzi Arpaci-Dusseau, and Miron Livny,
"Migratory File Services for Scientific Applications", in preparation.

John Bent, Douglas Thain, Andrea Arpaci-Dusseau, Remzi Arpaci-Dusseau,
and Miron Livny, "The I/O Requirements of Batch Parallel Sequential
Jobs", in preparation.

Douglas Thain and Miron Livny, "The Case for Sparse Files," in
preparation.

Douglas Thain and Miron Livny, "Fault Correctness in the Pluggable File
System," in preparation.

**Giggle: A Framework for Constructing Scalable Replica Location
Services.** Ann Chervenak, Ewa Deelman, Ian Foster, Leanne Guy, Wolfgang
Hoschek, Adriana Iamnitchi, Carl Kesselman, Peter Kunszt, Matei Ripeanu,
Bob Schwartzkopf, Heinz Stockinger, Kurt Stockinger, Brian Tierney. To
appear in Proceedings of SC2002 conference. Final copy submitted July
26, 2002.

**High-Performance Remote Access to Climate Simulation Data: A Challenge
Problem for Data Grid Technologies.** Ann Chervenak, Ewa Deelman, Carl
Kesselman, Bill Allcock, Ian Foster, Veronika Nefedova, Jason Lee, Alex
Sim, Arie Shoshani, Bob Drach, Dean Williams and Don Middleton.
Submitted to Parallel Computing Journal.

**Data Grid Architecture.** William Allcock, Ann Chervenak, Ewa Deelman,
Ian Foster, Carl Kesselman, Peter Kunszt, Erwin Laure, Arie Shoshani,
Heinz Stockinger, Kurt Stockinger, Douglas Thain. In progress.

**Presentations Given**

**Aug 2002** John Bent, "Flexibility, Manageability, and Performance in
a Grid Storage Appliance," HPDC-11, Edinburgh, Scotland

**Aug 2002** Douglas Thain, "Error Scope on a Computational Grid,"
HPDC-11, Edinburgh, Scotland

**July 2002** Douglas Thain, "Errors on the Grid: Theory and Practice,"
GriPhyn Reliability Workshop, Marina del Rey, California

**10-11 July 2002**: Workshop on Grid Reliability at USC Information
Sciences Institute

**20 July 2002** Presented \"The Globus Toolkit and OGSA\" at Sun High
Performance Computing Consortium Meeting in Glasgow, Scotland

**22 July 2002**: Presented Giggle Replica Location Service to
Replication Research Group at Global Grid Forum Meeting in Edinburgh,
Scotland.

**22 July 2002**: As Working Group Chair of Global Grid Forum
Replication Research Group, led working group discussion of work of
several groups on data replication in grids.

**23 July 2002** Conducted GridFTP working Group meeting iat Global Grid
Forum Meeting in Edinburgh, Scotland.

**24 July 2002** Conducted BOF session for formation of Data Transport
Research Group at Global Grid Forum Meeting in Edinburgh Scotland.

**August 2002**: Presented Replica Location Service and Metadata Catalog
Service to LIGO group meeting.

**12-13 September 2002**: Meeting between Globus and IBM on
opportunities for collaboration on data grid architectures and services.
Presented overviews of the Globus approach to data grid architecture,
the Giggle Replica Location Service Service, the GridFTP protocol and
the Reliable File Transfer Service.