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SHARING DATA USING THE STORAGE RESOURCE BROKER (SRB). Ken Wong The Applied Research Laboratory (ARL) and The Department of Computer Science Washington University in St. Louis kenw@arl.wustl.edu, http://www.arl.wustl.edu/~kenw. OUTLINE OF TALK. SRB and HPSS Overview
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SHARING DATA USING THE STORAGE RESOURCE BROKER (SRB) Ken Wong The Applied Research Laboratory (ARL) and The Department of Computer Science Washington University in St. Louis kenw@arl.wustl.edu, http://www.arl.wustl.edu/~kenw
OUTLINE OF TALK • SRB and HPSS Overview • SRB Concepts and Examples • Alternatives to SRB • Other SRB Projects • Our Experience
WU DATA CACHE • 1.4 TB DEC Storage Works RAID (Level 5) • 2-processor Sun Enterprise 450, 1 GB main memory • 622 Mbps ATM interface, 10/100 Mbps Ethernet interface • 1.7 TB (raw) = 48 x 9 + 24 x 18 + 24 x 36 GB • Backups • Incremental: Tue, Wed, Thu • Full: Mon, Fri, Sat • Data Volume • Used: 560 GB • Burn Rate: 7.0 GB/week (This Year); 5.5 GB/week (Lifetime)
INSTALLATION HISTORY • Jun/Jul 98: Sun host and then 432 GB RAID • 3 year extended warranty and 3 year maintenance on controllers • Sep 98: SRB • Aug 99: 24 x18.2 GB disks • 3 year maintenance upgrade on controllers • Dec 99: 24 x 36.4 GB disks
HIGH-PERFORMANCE STORAGE SYSTEM • Current Usage • 150 TB (terabytes; trillion) • 15 million files • Current Capacity: 500 TBs of data (assuming a compression ratio of 1.5) • Projected Capacity: 1 PB (10^15) within a year
SRB CONCEPTS • SRB Server: Responds to SRB requests from clients • MCAT (Metadata Catalogue) • Information about data sets and collections (Oracle DB) • SRB Client • SRB Resource: A logical storage resource • Example: HPSS storage and container cache • Data Set: A file registered with the SRB • Collection: Group of registered data sets/collections • Container: Data sets stored as one physical unit • Container cache can be remote from HPSS
SRB SYSTEM CAPABILITIES • Collection-based management of data sets • Persistent identifiers for data sets • Management of data sets (copies or replicas) • Containers for aggregating data sets before archiving • Support for grid security infrastructure authentication • Uses public key certificates • Support for integrating data set collections across file systems, archives, and databases
SRB INTERFACES • Scommands (Unix commands) • Sinit/Sexit, Sput/Sget, Smkdir/Srmdir, Sls/Srm • Smkcont/Ssyncont, Slscont/Srmcont • SgetR/SgetU/SgetD • C-Programming API • Browser
PUBLISHING A DATA SET • Define the SRB environment (.srb/.MdasEnv file) mdasCollectionHome ‘/home/kenw.neurodb’ mdasDomainHome ‘neurodb’ srbUser ‘kenw’ srbHost ‘ghidorah.sdsc.edu’ defaultResource ‘cont-sdsc’ • Interact with SRB server %Sinit # Connect to SRB server %sls # See what is in my collection %Sput ./mydata brain043 # Copy file to SRB space %Schmod r public npaci brain043 # Give read access %SgetD -a brain043 # Check access permissions %Sexit # disconnect from SRB server
GETTING A DATA SET (SCOMMANDS) % Sinit % Scd /home/colin.neurodb # go to Colin's collection % Sls -l # see what is there % Sget colin_avg20_1.0mm_at0.5mm.mnc . # copy to this directory % Sexit
JINGHUA ZHOU'S WORK • Experiments • Test SRB functionality • Measures performance of basic SRB functions • Archiving (Perl Scripts) • Archive an arbitrary Unix directory to HPSS • Verify files were archived • Recover files from archival storage
RETRIEVAL EXPERIMENTS • Load 100 MB container with 1 MB files • Measure time required to retrieve N files • Divide time by N to get average time for each file • Repeat after container has been moved to tape • Repeat above steps for 10 MB container (instead of 100 MB)
COMMENTS • SRB Overhead Per Object (File) • 5-7 seconds (Early Measurements) • 2-4 seconds (Recent Measurements) • Tape Overhead Per Object (File): 100 seconds • TCP Connection Needs Tuning • Assymetric routing, bottleneck, ... • snoop and tcptrace analysis • Max Sget effective bandwidth is 8 Mbps • Max Sput effective bandwidth is 4 Mbps • Goal is 32 Mbps
ARCHIVING • Reflect Unix directory structure in SRB collection structure • archiver NPACI/Unix account • Look for inactive files within a directory • Multiple versions handled by appending modification date to file name • Log all archival requests
CURRENT WORK • TCP Tuning and SRB 1.1.7 Performance • Enhance Archival Scripts • Improve usability • Resilience to HPSS Blackouts • Parallel Archiving
RECENT SRB DEVELOPMENTS • Data Cutter • GSI authentication • UsesX.509 certificates • Container redesign • To handle multiple archival and cache resources • Remote proxy (Spcommand) • Textual annotation stored in MCAT
ALTERNATIVES TO SRB • Distributed Database • Do not deal with file data => Requires other means of accessing files • A heavyweight solution; i.e., expense (money, expertise) • Need instances running wherever you want to have storage • If it is only meta-data, then a case can be made but ... • Tied to a particular vendor at all sites • Have to cross link all the databases • AFS (Andrew File System) • Doesn't have concept of application metadata • SRB has some metadata facilities now and more to come • Comments, annotations, user-controlled metadata • SRB provides a uniform authentication and authorization system
TOP SRB PROJECTS (SUMMARY) • 2-Micron All Sky Survey • 10 TB of data from Caltech • 5 million images sorted into 130,000 containers • Digital Embryo Project (NLM funded) • Digitizing existing slides for storage in HPSS • Particle Physics Data Grid (DOE funded) • Data mining • Information Power Grid (NASA funded) • Data Visualization Corridor (DOE funded) • Handles terabyte sized data sets for interactive viewing • Neuroscience Data Set Federation
TOP SRB PROJECTS • 2-Micron All Sky Survey (2MASS) • 10 TB of data from Caltech (3 TB done) • 5 million images sorted into 130,000 containers • SRB container technology used to manage the aggregation process on a disk cache • Replicate Caltech data • Digital Embryo Project (NLM funded) • Digitizing existing slides for storage in HPSS • SRB used to manage data movement, aggregation into containers, and metadata catalog • Queries against the collection • Particle Physics Data Grid (DOE funded) • Replicate data sets that are pulled into local disk caches
TOP SRB PROJECTS • Information Power Grid (NASA funded) • SRB used to support data mining against a distributed data set collection • Data transmission rate: 58 Mbps from SDSC to NASA Ames • Put collection management in front of storage archives through use of the MCAT • Data Visualization Corridor (DOE funded) • SRB has been integrated with the Data Cutter system • For remote manipulation of data sets • Handles terabyte sized data sets for interactive viewing • Neuroscience Data Set Federation
CONCLUDING REMARKS • Documentation • http://www.sdsc.edu/DICE/SRB/index.html • http://www.arl.wustl.edu/kenw/npaci/index.html • Software • Follow SRB link • Get PGP key from SDSC • Can install subset (e.g., client only) • Applications?
WU DATA CACHE vBNS 45 Mbps ATM sdsc.edu wustl.edu 622 Mbps 155 Mbps ghidorah (MCAT) hpss brainmap (1.3 TB) stp, v1 (SUMS) petsun-23 (Scanners) (12 Major Users) UCSD, UCLA, John Hopkins, U. Montana, Caltech