Data Grid: GRASP
Mike Smorul
<toaster@umiacs.umd.edu>
Grid Retrieval and Search Platform
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)

Earth Science Data Interface
ESDI Overview
Designed to allow for intuitive browsing
and searching of large geospatial data
sets.
 Tightly integrated set of web, ftp, and file
servers. (customized to GLCF)
 Distributes over 7Tb of data per month
 Over 27,000 Landsat scenes and 13Tb of
data available for download

SRB Grid Testbed (original)
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Modified the SRB to hold spatial data
Contributed Informix port of the SRB (v3.2)
Linked three ESIP sites
Tested replication between
GMU and UMD.
Remote registration at
UNH
Informix
UMD MCAT enabled srbmaster

MSS(2)
GMU srbmaster
TM
MSS(1)
UMD srbmaster
with dfs access
MODIS
UNH srbmaster
Lessons Learned
The SRB can easily handle textual
metadata.
 Spatial data could be stored into extended
Informix attributes, but querying was
available only through the DAI

 Limited
SRB MCAT to Informix based systems
GRASP Architecture
Spatial
Information
Data Grid
Textual
Information
Query Abstraction
I/O Abstraction Layer
Browse / Display
Data Discovery
Data download
Clients
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
Grid Holdings

Registered GLCF holdings
 Over
338,000 registered files
 4.4Tb total size
 Granular permissions on registered holdings
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No need to move all data into grid,
registered pre-existing holdings in place.
Current data grid
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Designed using newer SRB software that allows
for Federated grid model.
Created using standard SRB software
configuration (postgreSQL)
Large data sites can maintain independent
MCATs
 Administratively
independent
 Ability to customize data grid to site security/data
requirements while maintaining compatibility across
federation.

Smaller peers can register as clients of UMD
Data grid overview
GRASP Interface
Zone: esip-remote
Remote MCAT
SRB Master
SRB Master
SRB Master
Zone: esip-umiacs
UMD MCAT
SRB Master
SRB Master
DFS
Gateway
Local Peer
Growing data grid
Additional MCATs can be federated
 Additional SRB aware clients can be
added
 Remote data supplying sites can
contribute data sets from their resources
 Sites needing quick local access to data
can replicate to local SRB setup.

Questions?