Integration of Data Grids, Digital Libraries, and Persistent

Integration of Data Grids, Digital Libraries, and Persistent

Integration of Data Grids, Digital Libraries, and Persistent Archives (Storage Resource Broker - SRB) Arcot Rajasekar Michael Wan Reagan W. Moore (sekar, mwan, moore)@sdsc.edu San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure SDSC SRB Team

Reagan Moore Michael Wan Arcot Rajasekar Wayne Schroeder Arun Jagatheesan Charlie Cowart Lucas Gilbert George Kremenek Sheau-Yen Chen Bing Zhu Roman Olschanowsky (BIRN) Vicky Rowley (BIRN) Marcio Faerman (SCEC) Antoine De Torcy (IN2P3) Students & emeritus San Diego Supercomputer Center Erik Vandekieft

Reena Mathew Xi (Cynthia) Sheng Allen Ding Grace Lin Qiao Xin Daniel Moore Ethan Chen Jon Weinburg National Partnership for Advanced Computational Infrastructure Topics Concepts behind data management Production data grid examples Integration of data grids with digital libraries and persistent archives San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Data Grid Support data sharing between institutions Discover relevant data without knowing the file name Access data without knowing the storage location or storage access protocol Retrieve data using your preferred API Organize distributed data in a collection hierarchy Manage latency in wide-area-networks

Manage PetaBytes of data and hundreds of millions of files San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Digital Library Provide curation services Organization, description, and management of data Support schema extension Provide access services Discovery, browsing, presentation, and manipulation of data Federate semantics across collections Digital library crosswalks San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Persistent Archive Support archival processes Appraisal, accession, arrangement, description, preservation, and access Manage technology evolution while preserving integrity and authenticity of data

Minimize risk of data loss Preserve collections for hundreds of years Data replication San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Challenges Each community assigns different meanings to terms used to describe their requirements Data grid community Persistent Archive is the infrastructure that manages storage technology evolution while preserving a collection Archivist community Persistent Archive is the collection that is being preserved in some choice of infrastructure Together they define a preservation environment San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Challenges Preservation community traditionally views technology evolution as the problem rather than the solution Preservation requires the ability to manipulate old formats

Digital library community attempts to assert exact meaning for semantics. Metadata Encoding and Transmission Standard is one approach towards the creation of a metadata framework with the ability to support extension schema Data grid community has not chosen standards for distributed data management Computer science is just starting to understand how to characterize and manage data, information, and knowledge San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure To Make Progress Develop simplest possible description for describing data, information, and knowledge management Identify common infrastructure components Apply in production settings Iterate, based on new expectations for data management San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Common Requirements for

Data Management Distributed data sources Management across administrative domains Heterogeneity Multiple types of storage repositories Scalability Support for billions of digital entities, PetaBytes of data Preservation Management of technology evolution San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure SRB Collections at SDSC Project Instance As of 12/22/2000 Data_size Count (in GB) (files) As of 5/17/2002 Data_size Count (in GB)

(files) As of 3/3/2004 Data_size (in GB) Count (files) Data Grid Digsky 7,599.00 3,630,300 17,800.00 5,139,249 45,939.00 8,685,572 46,844 NPACI 329.63 1,972.00 1,083,230 13,700.00 4,050,863 Hayden 6,800.00 41,391 7,835.00 60,001 SLAC -JCSG

514.00 77,168 3,432.00 446,613 LDAS/SALK 239.00 1,766 2,002.00 14,427 TeraGrid 22,563.00 452,868 BIRN 892.00 2,472,299 Digital Library DigEmbryo 124.30 2,479 433.00 31,629 720.00 45,365 HyperLter 28.94 69 158.00 3,596 215.00 5,110

Portal 33.00 5,485 1,610.00 46,278 AfCS 27.00 4,007 236.00 42,987 NSDL/SIO Exp 19.20 383 1,217.00 193,888 Transana 5.80 92 92.00 2,387 SCEC 12,311.00 1,730,432 UCSDLib 127.00 202,445 Persistent Archive NARA/Collection 7.00 2,455

72.00 82,192 NSDL/CI 1,529.00 12,658,072 TOTAL 8 TB 3.7 million 28 TB 6.4 million 114 TB 31 million ** Does not cover data brokered by SRB spaces administered outside SDSC. Does not cover databases; covers only files stored in file systems and archival storage systems Does not cover shadow-linked directories San Diego Supercomputer Center Users 80 379 168 43 66 2,585 160 23 29 374 21 26

26 47 29 58 116 4230 National Partnership for Advanced Computational Infrastructure Data Management Concepts (Elements) Collection The organization of digital entities to simplify management and access. Context The information that describes the digital entities in a collection. Content The digital entities in a collection San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Types of Context Metadata Descriptive Provenance information, discovery attributes

Administrative Location, ownership, size, time stamps Structural Data model, internal components Behavioral Display and manipulation operations Authenticity Audit trails, checksums, access controls San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Metadata Standards METS - Metadata Encoding Transmission Standard Defines standard structure and schema extension OAIS - Open Archival Information System Preservation packages for submission, archiving, distribution OAI - Open Archives Initiative Metadata retrieval based on Dublin Core provenance attributes San Diego Supercomputer Center

National Partnership for Advanced Computational Infrastructure Data Management Concepts (Mechanisms) Curation The process of creating the context Closure Assertion that the collection has global properties, including completeness and homogeneity under specified operations Consistency Assertion that the context represents the content San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Information Technologies Data collecting Sensor systems, object ring buffers and portals Data organization Collections, manage data context Data sharing Data grids, manage heterogeneity

Data publication Digital libraries, support discovery Data preservation Persistent archives, manage technology evolution Data analysis Processing pipelines, manage knowledge extraction San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Assertion Data Grids provide the underlying abstractions required to support Digital libraries Curation processes Distributed collections Discovery and presentation services Persistent archives Management of technology evolution Preservation of authenticity The management of data requires the use of information (semantic labels). The management of information requires the use of knowledge (relationships).

San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Data Grid Terms Data Bits - zeros and ones Digital Entity The bits that form an image of reality (file, object, image, data, metadata, string of bits, structured sets of string of bits) Information Semantic labels applied to data Metadata Semantic label and the associated data (attribute name and attribute value) Knowledge Relationships between semantic labels applied to data Relationships used to assert the application of a semantic label San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Data Grid Components Federated client-server architecture Servers can talk to each other independently of the client

Infrastructure independent naming Logical names for users, resources, files, applications Collective ownership of data Collection-owned data, with infrastructure independent access control lists Context management Record state information in a metadata catalog from data grid services such as replication Abstractions for dealing with heterogeneity San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Data Grid Abstractions Logical name space for files Global persistent identifier Storage repository virtualization Standard operations supported on storage systems Information repository virtualization Standard operations to manage collections in databases Access virtualization Standard interface to support alternate APIs

Latency management mechanisms Aggregation, parallel I/O, replication, caching Security interoperability GSSAPI, inter-realm authentication, collection-based authorization San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Storage Repository Virtualization User Application Archive San Diego Supercomputer Center Database File System National Partnership for Advanced Computational Infrastructure Storage Repository Virtualization Remote operations Unix file system Latency management Procedures Transformations Third party transfer

Filtering Queries User Application Common set of operations for interacting with every type of storage repository Archive San Diego Supercomputer Center Database File System National Partnership for Advanced Computational Infrastructure Mappings on Resource Name Space Define logical resource name List of physical resources Replication Write to logical resource completes when all physical resources have a copy Load balancing Write to a logical resource completes when copy exist on next physical resource in the list

Fault tolerance Write to a logical resource completes when copies exist on k of n physical resources San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Containers Archivists store hardcopy in cardboard boxes A container is the digital equivalent, the aggregation of digital files into a single file, with an associated packing list Containers are used to minimize access latency, keep similar digital entities together San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Data Stored at SDSC HPSS archive Stores 1 Petabyte of data Stores 17 million files Storage Resource Broker data grid Stores 114 Terabytes of data Stores 31 million files

Containers are used to aggregate files before loading into HPSS San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure SDSC Storage Resource Broker & Meta-data Catalog Application C, C++, Linux Libraries I/O Unix Shell Java, NT Browsers DLL / Python GridFTP OAI WSDL Consistency Management / Authorization-Authentication

Logical Name Latency Space Management Catalog Abstraction Databases DB2, Oracle, Sybase, SQLServer San Diego Supercomputer Center Data Transport Metadata Transport Storage Abstraction Archives File Systems Databases HPSS, ADSM, HRM UniTree, DMF Unix, NT, Mac OSX DB2, Oracle, Postgres Access

APIs SRB Server Drivers National Partnership for Advanced Computational Infrastructure Production Data Grid SDSC Storage Resource Broker Federated client-server system, managing Over 100 TBs of data at SDSC Over 25 million files Manages data collections stored in Archives (HPSS, UniTree, ADSM, DMF) Hierarchical Resource Managers Tapes, tape robots File systems (Unix, Linux, Mac OS X, Windows) FTP sites Databases (Oracle, DB2, Postgres, SQLserver, Sybase, Informix) Virtual Object Ring Buffers

San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Data Virtualization User Application Archive at SDSC San Diego Supercomputer Center Database At U Md File System at U Texas National Partnership for Advanced Computational Infrastructure Data Virtualization Logical name space Location independent identifier Persistent identifier Collection owned data Access controls Audit trails Checksums Descriptive metadata Inter-realm authentication

Single sign-on system San Diego Supercomputer Center User Application Common naming convention and set of attributes for describing digital entities Archive at SDSC Database At U Md File System at U Texas National Partnership for Advanced Computational Infrastructure Logical Name Space Persistent, location-independent identifiers for digital entities Organized as collection hierarchy Attributes mapped to logical name space Attributed managed in a database Types of administrative metadata Physical location of file Owner, size, creation time, update time

Access controls San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure File Identifiers Logical file name Infrastructure independent Used to organize files into a collection hierarchy Globally unique identifier GUID for asserting equivalence across collections Descriptive metadata Support discovery Physical file name Location of file San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Information Repository Virtualization Operations used to manage administrative, descriptive, user-defined metadata Import from XML file Export to XML file Bulk load

Bulk unload Schema extension Access controls Dynamic SQL generation San Diego Supercomputer Center User Application Common operations for managing a catalog in a database Choice of database for Metadata Catalog National Partnership for Advanced Computational Infrastructure Map from API to remote operations Unix file system Latency management Procedures Transformations Third party transfer Filtering Queries Access Virtualization Application

C, C++, Linux Libraries I/O Unix Shell Java, NT Browsers DLL / Python GridFTP OAI WSDL Common operations performed on all storage repositories San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Technology Evolution All components of the Persistent Archive will evolve

Hardware systems Software systems Protocols Access methods Encoding syntax for digital entities Create drivers for each new storage repository protocol Migrate data to each new storage system Manage evolution of the encoding syntax through either transformative migration or emulation San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Are Repeated Media Migrations Feasible? At SDSC, cartridge capacity has increased from 200 Mbytes to 200 Gbytes for same cartridge cost Only migrate to new technology when the cost per Gigabyte is a factor of two lower Then the media cost is fixed when sum over all migrations (1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + ) = 2 SDSC migrates to new media to reduce cost

All tape are stored in robots to minimize labor costs San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Transformative Migration versus Emulation versus Digital Ontology Transformative Migration Transform the encoding format to a new standard Can combine encoding format transformation with media migration Emulation Create a transportable parser for the original encoding format Migrate emulator forward in time Example - Multivalent Browser (written in Java) for parsing pdf, laTex, Digital ontology Characterize the structures and relationships present within the digital entity Migrate the characterization forward in time San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Persistent Archives When migrate from an old technology to a new technology, both versions are available. Virtualization mechanisms used for federation across space can be used to manage migration

over time Persistent archives can be built on data grid infrastructure San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Automation of Archival Processes Archival Process Functionality Appraisal Assessment of digital entities Accession Import of digital entities Description Assignment of preservation metadata Arrangement Logical organization of digital entities Preservation Long-term storage

Access Discovery and retrieval San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Data Grid Core Capabilities Storage repository abstraction Storage interface to at least one repository Standard data access mechanism Standard data movement protocol support Containers for data Logical name space Registration of files in logical name space Retrieval by logical name Logical name space structural independence from physical file Persistent handle San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Information Repository Abstraction Collection owned data Collection hierarchy for organizing logical name space

Standard metadata attributes (controlled vocabulary) Attribute creation and deletion Scalable metadata insertion Access control lists for logical name space Attributes for mapping from logical file name to physical file Encoding format specification attributes Data referenced by catalog query Containers for metadata San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Distributed Resilient Architecture Specification of system availability Standard error messages Status checking Authentication mechanism Specification of reliability against permanent data loss Specification of mechanism to validate integrity of data Specification of mechanism to assure integrity of data San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Virtual Data Grid Knowledge repositories for managing collection properties Characterization of the application of transformative migrations on encoding format

Characterization of the application of archival processes San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Federated SRB server model Read Application Logical Name Or Attribute Condition Peer-topeer Brokering Parallel Data Access 1 6 SRB server 3 San Diego Supercomputer Center

SRB server 4 SRB agent 5 SRB agent 1.Logical-to-Physical mapping 2.Identification of Replicas 3.Access & Audit Control 5/6 2 R1 MCAT Data Access R2 Server(s)

Spawning National Partnership for Advanced Computational Infrastructure Latency Management Bulk Operations Bulk register Create a logical name for a file Load context (metadata) Bulk load Create a copy of the file on a data grid storage repository Bulk unload Provide containers to hold small files and pointers to each file location Bulk delete Requests for bulk operations for access control, San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure SRB Latency Management Remote Proxies, Staging Source Data Aggregation Containers

Network Network Replication Streaming Server-initiated I/O Parallel I/O San Diego Supercomputer Center Prefetch Destination Destination Caching Client-initiated I/O National Partnership for Advanced Computational Infrastructure Southern California Earthquake Center Build community digital library Manage simulation and observational data Anelastic wave propagation output 10 TBs, 1.5 million files Provide web-based interface

Support standard services on digital library Manage data distributed across multiple sites USC, SDSC, UCSB, SDSU, SIO Provide standard metadata Community based descriptive metadata Administrative metadata Application specific metadata San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure SCEC Digital Library Technologies Portals Knowledge interface to the library, presenting a coherent view of the services Knowledge Management Systems Organize relationships between SCEC concepts and semantic labels Process management systems Data processing pipelines to create derived data products

Web services Uniform capabilities provided across SCEC collections Data grid Management of collections of distributed data Computational grid Access to distributed compute resources Persistent archive Management of technology evolution San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Metadata Organization (Domain View versus Run View) Provenance Velocity Model

Simulation Model Fault Model Program Domain Spatial Physical Computer System ... Temporal Numerical Run Output Domain List San Diego Supercomputer Center Formatting National Partnership for Advanced Computational Infrastructure San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure

San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Zone SRB Federation Mechanisms to impose consistency and access constraints when sharing: Resources Controls on which zones may use a resource User names (user-name / domain / SRB-zone) Users may be registered into another domain, but retain their home zone, similar to Shibboleth Data files Controls on who specifies replication of data Context metadata Controls on who manages updates to metadata San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Data Grid Federation zoneSRB C, C++, Java Linux Libraries I/O Unix Shell

Application Java, NT Browsers DLL / Python, Perl HTTP OAI, WSDL, OGSA Federation Management Consistency & Metadata Management / Authorization-Authentication Audit Logical Name Space Catalog Abstraction Databases DB2, Oracle, Sybase, Postgres, mySQL, Informix San Diego Supercomputer Center Latency Management

Data Transport Metadata Transport Storage Repository Virtualization Databases Archives - Tape, File Systems DB2, Oracle, Sybase, HPSS, ADSM, ORB Unix, NT, SQLserver,Postgres, UniTree, DMF, Mac OSX mySQL, Informix CASTOR,ADS National Partnership for Advanced Computational Infrastructure Peer-to-Peer Federation 1. 2. 3. 4. 5. Occasional Interchange - for specified users Replicated Catalogs - entire state information replication Resource Interaction

- data replication Replicated Data Zones - no user interactions between zones Master-Slave Zones - slaves replicate data from master zone 6. Snow-Flake Zones 7. User / Data Replica Zones zone - hierarchy of data replication zones - user access from remote to home 8. Nomadic Zones SRB in a Box parent zone 9. Free-floating myZone 10. Archival BackUp Zone - synchronize local zone to - synchronize without a parent zone - synchronize to an archive SRB Version 3.0.1 released December 19, 2003 San Diego Supercomputer Center

National Partnership for Advanced Computational Infrastructure Principle peer-to-peer federation approaches (1536 possible combinations) Zone SRB Zone Organization Zones Zone interaction control Consistency Management Zones Collections User Connection Point to access files Files Data Access Control

Setting Metadata synchronization Resource sharing User-ID sharing between zones Files Metadata Resources User names Free Floating Zones Peer-to-Peer Local Admin User-specified data publication

From home zone User set access controls User controlled synchronization None None Occasional Interchange Peer-to-Peer Local Admin User specified From home zone User set access controls User controlled synchronization

None Partial Replicated Data Zones Peer-to-Peer Local Admin User-specified replication From home zone User set local access controls User controlled synchronization Partial Partial, user establishes own accounts

Resource Interaction Peer-to-Peer Local Admin User-specified replication From home zone User set access controls None Partial shared resource for replication Partial User and Data Replica Zones Peer-to-Peer Local Admin

User-specified replication From home zone System set access controls System controlled complete synchronization Partial Complete Replicated Catalog Peer-to-Peer Local Admin System managed System System controlled All zones share name conflict

From any zone replicated complete resources resolution access controls synchronization From home zone System set access controls System controlled partial synchronization None One Complete Snow Flake Zones Hierarchical Local Admin System managed

replication in hierarchy of zones Master-Slave Zones Hierarchical Super Admin System-managed replication to slave From home zone System set access controls System controlled partial synchronization None One Archival zones

Hierarchical Super Admin System-managed versioning to parent zone From home zone System set access controls System controlled complete synchronization None Complete Nomadic Zones Hierarchical Local Admin User-managed

replication to parent zone San Diego Supercomputer Center From home User set access zone controls for National Partnership User controlled Partial One synchronization Advanced Computational Infrastructure Peer-to-Peer Zones Free Floating Partial User-ID Sharing Occasional Interchange Partial Resource Sharing Replicated Data System Set Access Controls System Controlled Complete Synch Complete User-ID Sharing

User and Data Replica System Managed Replication Connection From Any Zone Complete Resource Sharing Replicated Catalog Replication Zones No Metadata Synch Resource Interaction Hierarchical Zone Organization One Shared User-ID Nomadic System Managed Replication System Set Access Controls System Controlled Partial Synch No Resource Sharing Snow Flake Super Administrator Zone Control Master Slave System Controlled Complete Synch Complete User-ID Sharing Archival Hierarchical Zones San Diego Supercomputer Center

National Partnership for Advanced Computational Infrastructure Deep Archive Impose sharing constraints: Only system administrator access Selected replication of files Write once, with versions created on changes to data Impose consistency constraints Coordinate update of preservation metadata with file replication Manage replication of both data and metadata Use federation to guarantee preservation against Local hardware and software failures Local operation errors Local disasters San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Research Information (semantic label) is an assertion that some criteria were met for the application of the label Need to describe and manage the assertions (rules and relationships) used to apply semantic labels Information (semantic label) expresses a context-related meaning that should be associated with a digital entity Meaning is determined by the context

Characterization of information requires the ability to describe The context that defines the assertions for assigning the label The context that explains the meaning of the label Organization of information requires the use of relationships (knowledge) San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure Knowledge Based Data Grid Roadmap Knowledge Repository for Rules Access Services Rules - KQL Knowledge Relationships Between Concepts Management XTM DTD

Ingest Services Knowledge or Topic-Based Query / Browse Attributes Semantics Information Repository SDLIP Information XML DTD (Model-based Access) Attribute- based Query Fields Containers Folders San Diego Supercomputer Center

Storage (Replicas, Persistent IDs) Grids Data MCAT/HDF (Data Handling System) Feature-based Query National Partnership for Advanced Computational Infrastructure For More Information Reagan W. Moore San Diego Supercomputer Center [email protected] http://www.npaci.edu/DICE http://www.npaci.edu/DICE/SRB http://www.npaci.edu/dice/srb/mySRB/mySRB.html San Diego Supercomputer Center National Partnership for Advanced Computational Infrastructure

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