Mike Smorul

Saurabh Channan

Digital Preservation and Archiving at the

Institute for Advanced Computer StudiesUniversity of Maryland, College Park

Overview

• Digital Preservation Research– ADAPT Project and Components– Pilot Persistent Archive

• Digital Library and Production Data Distribution– Global Land Cover Facility

• Conclusion & Questions

A Digital Approach to Preservation Technology (ADAPT)

• Premise:– Preservation of digital entities into self-

describing objects• OAIS Information Packet model as a framework

– Separation of management into three layers, bitstream, semantic, and access/discovery

– Distributed and Secure Infrastructure• Automatic ingestion and replication• Policy-Driven Management of Preservation

Processes• Global Format Registry• Separate Peer-to-Peer Deep Archive

ADAPT Architecture

Data Management

Metadata Management

Descriptive Metadata

Preservation Metadata

Administrative Metadata

Deep Archive Data GridConventional

Archive

PAWN

Met

adat

a

Data

CAN

Management of Preservation Processes

ADAPT Components• Ingestion

– Producer-Archive Workflow Network (PAWN)

• Management of Preservation Processes– Lightweight Preservation Environment (LPE)

• Access and Discovery– Grid Retrieval and Search Platform (GRASP)– EAP Collection browser

Overall Principles (PAWN)

• Distributed, secure ingestion• OAIS based Information Packet creation• Use of web/grid technologies – platform

independent• Minimal client-side requirements• Ease of integration with archive and data grid

systems.• Designed to satisfy data integrity requirements

of scientific collections and digital preservation

Distributed Ingestion (PAWN)

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Producer

``

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Producer

``

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Producer

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Producer

Distributed Archive

Ingestion Workflow (PAWN)

1. Negotiate Submission Agreement.

2. Workflow Initialization and Submission Information Packet (SIP) creation.

3. Transfer of SIPs to Data Grid site.

4. Validation of SIP transfer

5. Organization of data into collections and transfer into Data Grid.

Component Overview (PAWN)

CRL check

Success/Failure notification of ingestion

Metadata registration/retrieval

Producer Management Interface Data Grid Management Interface

Producer data suppliersBitstream Validation Service

Data Grid

Target Collections (PAWN)

• Digital Image Collection– Rich metadata in various formats

• Web site crawling– Online and interactive content

• GLCF Landsat data– Spatial and temporal metadata– Large quantity (over 15,000 objects)

•The Lightweight Preservation Environment is an archival system based on a modular design using grid and web services.

•The current implementation relies mostly on Globus technologies.

•Primarily, we’ve focused on wrapping logic around those components.

Lightweight Preservation Environment (LPE)

Developed Components (LPE)

•Data Manager (DM):Organizes data and queries between the user and the other components

•Policy Manager (PM):Ensures that a minimum number of copies exist for any given file

•Transformation Manager (TM):Executes specific transformations on a named file on a given storage node and returns the results

Grid Retrieval and Search Platform (GRASP)

• Based on concepts developed in the Earth Science Data Interface (ESDI) developed at the UMIACS GLCF.

• Provides a graphical interface into data grid holdings.

• Access to entire GLCF holdings through the Storage Resource Broker(SRB)

GRASP Architecture

I/O Abstraction Layer

Data Grid

Clients

Data download

Query Abstraction

Browse / Display

Spatial Information

Textual Information

Data Discovery

GRASP Architecture

• GRASP uses a data grid as an abstract storage repository.

• Metadata in the grid is mined from the grid itself or from external sources and published into a browsable form.– Data grids may allow for platform independent

metadata, but may not be optimal for access

GRASP Screenshot

Global Land Cover Facility• Mission:

“The GLCF Mission is to encourage the use of remotely sensed imagery, derived products and applications within a broad range of science communities in a manner that improves comprehension of the nature and causes of land cover change and its impact on the Earth.”

• Goal:“The GLCF Goal is to provide free access to an integrated

collection of critical land cover and Earth science data through systems that are designed to maximize user outreach and that promote development of novel tools for ordering, visualizing and manipulating spatial data.”

Data Collections

Majority of the holdings are of Landsat and MODIS data

Data Distribution

• Data at the GLCF– Approximately 5.1 TB

compressed– Approximately 13 TB

uncompressed

• Anticipated Production Rate– Triple or Quadruple current

data holding within the next two year

Data Traffic

0

2,000,000

4,000,000

6,000,000

8,000,000

10,000,000

12,000,000

Month

Meg

abyt

es

Data Discovery Applications

ESDI

Web Interface

User friendly

Search

Retrieve

Discover

Scalable

Over 9TB a month !

GLCF Archive

SunFire V100

Sun

SunFire V100

SunSunFire V100

Sun

SunFire V100

Sun

SunFire V100

Sun

SunFire V100

Sun

SunFire V100

Sun

SunFire V100

Sun

ProFTPd servers

File ServersRAIDs

ftp://ftp.glcf…./../something.tif

SunFire V100

Sun

SunFire V100

Sun

SunFire V100

Sun

Scalable and Reliable

Participation Possibilities

• PAWN ingestion component– Minimal geospatial metadata support planned, can be

expanded to support NGDA endpoint

• GRASP display component– Solid core components, end-user interfaces need

additional polishing

• GLCF data holdings– Additional hardware required if additional data and

access mechanisms (grid, etc) required

• Other possibilities include: grid infrastructure, GSI security, format registry, etc.

Questions