Big Data: Indexing ~50Tb of URIs
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Presentation at the Big Data interest group at Los Alamos National Laboratory, regarding with with the IIPC to merge the indexes of multiple web archives.
![Using DISC to Reindex ~50Tb of URIs
Robert Sanderson
rsanderson@lanl.gov
@azaroth42
Herbert Van de Sompel
herbertv@lanl.gov
@hvdsomp
http://www.mementoweb.org/
Towards Seamless Navigation of the Web of the Past
Big Data Interest Group, LANL, Feb 21st 2013 1
[Unclassified]](https://image.slidesharecdn.com/bigdig-lanl-feb13-130220163736-phpapp02/85/big-data-indexing-50tb-of-uris-1-320.jpg)
![Summary
Memento
Project Overview
Participants
The Plan …
… and the Reality
Technical Details
Next Run
Big Data Interest Group, LANL, Feb 21st 2013 2
[Unclassified]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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Big Data: Indexing ~50Tb of URIs
- 1. Using DISC to Reindex ~50Tb of URIs Robert Sanderson rsanderson@lanl.gov @azaroth42 Herbert Van de Sompel herbertv@lanl.gov @hvdsomp http://www.mementoweb.org/ Towards Seamless Navigation of the Web of the Past Big Data Interest Group, LANL, Feb 21st 2013 1 [Unclassified]
- 2. Summary Memento Project Overview Participants The Plan … … and the Reality Technical Details Next Run Big Data Interest Group, LANL, Feb 21st 2013 2 [Unclassified]
- 3. Memento Project “ Provide web citizens seamless access to the web of the past ” Some accolades: • $1M funding from the Library of Congress • Winner of 2010 International Digital Preservation Award • Accepted by International Internet Preservation Consortium as the way forwards for access to web archives • Nominated for Best Paper at JCDL 2010 • Best Poster at JCDL 2012 • Tim Berners-Lee @ LDOW10: “We absolutely need this” • Internet Draft 6 (final call) by May Big Data Interest Group, LANL, Feb 21st 2013 3 [Unclassified]
- 4. Old Copies have New Names Everyone knows the URL for CNN is: http://www.cnn.com/ Everyone knows the URL for CNN was: http://www.cnn.com/ Big Data Interest Group, LANL, Feb 21st 2013 4 [Unclassified]
- 5. Old Copies have New Names Copies of the past versions of to http://www.cnn.com/ exist … but you don’t go there to get them, they have new URLs … and there’s no way to automatically discover those new URLs http://web.archive.org/web/20031013111028/http://www2.cnn.com/ Big Data Interest Group, LANL, Feb 21st 2013 5 [Unclassified]
- 6. Discovery is Hard People want to find, not search … and especially not searching by hand! http://web.archive.org/web/*/http://www2.cnn.com/ Big Data Interest Group, LANL, Feb 21st 2013 6 [Unclassified]
- 7. Navigating in the Past Links to the real resource bring you back out of the past … or trap you in a single incomplete archive. Pentagon Dec 20 2001, 4:51:00 UTC current http://web.archive.org/web/*/http://www2.cnn.com/ Big Data Interest Group, LANL, Feb 21st 2013 7 [Unclassified]
- 8. Memento: Time Travel for the Web TimeGate: Resource that knows the locations of archived copies Memento: An archived copy of previous state of a web resource Link header to TimeGate 302 redirect to Memento How does the TimeGate know where the appropriate Memento is? Big Data Interest Group, LANL, Feb 21st 2013 8 [Unclassified]
- 9. Project Overview Goal: • To aggregate the metadata of the distributed archives of the IIPC, and • To provide Memento based access to the holdings of open archives • To provide knowledge of the holdings of restricted archives • To provide knowledge to IIPC members of the holdings of totally closed archives Big Data Interest Group, LANL, Feb 21st 2013 9 [Unclassified]
- 10. Experiment Participants • Austrian National Library • Bibliothèque Nationale de France • British Library • Institut National de l'Audiovisuel • Internet Archive • Koninklijke Bibliotheek • Library of Congress • Netarchive.dk • Swiss National Library • University of North Texas • Los Alamos National Laboratory • Old Dominion University Big Data Interest Group, LANL, Feb 21st 2013 10 [Unclassified]
- 11. Data Canonical URL kosovakosovo.com/photo.php?id=5785 Datestamp 20090608161553 Request URL http://www.kosovakosovo.com/photo.php?id=5785 MIME type text/html HTTP Status 200 Checksum M36MRHSBVPLKMUN6PFOIEV3AH5ADITAN Redirect? - Bytes 563096 Storage File AIT-1068-20090608161511.warc.gz Multiplied by 6Tb compressed, ~50Tb uncompressed Big Data Interest Group, LANL, Feb 21st 2013 11 [Unclassified]
- 12. The Plan… • To provide fast access to distributed archives, LANL would merge the indexes of the holdings of multiple archives and provide Memento based access • Step 1: Library of Congress gathers CDX files Step 2: LANL indexes (a.k.a. “…”) Step 3: Profit • Data: 6T of gzipped CDX files (mostly from IA) • Shipped on hard drives • Computing: 210 node DISC cluster at LANL • 2x 2ghz processors, 2x 2T HDD, 8G RAM Big Data Interest Group, LANL, Feb 21st 2013 12 [Unclassified]
- 13. … and the Reality • Hardware failure killed one of the drives en route • Transferred remaining files via BagIt from LoC • DISC has restricted access: • Had to transfer data over intranet • 2 weeks to sync (5Mb/sec) • And then 2 weeks to get the processed results off • Compute cluster has faulty switch, unreliable nodes: • Ran original processing 15 times without success due to hardware failures Big Data Interest Group, LANL, Feb 21st 2013 13 [Unclassified]
- 14. Processing Design • For each CDX file, • For each URI + timestamps, • Map URI to an appropriate database slice • Merge timestamps with those of previous CDXs • Possible because: • No need to do truncated search • No need to walk through URIs in order • No need for time based access, only URI • Problem is “Embarrassingly Parallel” Big Data Interest Group, LANL, Feb 21st 2013 14 [Unclassified]
- 15. Approach 1: Online Messaging • 25 read nodes, 1 control node, 150 write nodes • Messages (1000 URIs) sent via control node to write • Failed 15 times due to hardware issues Big Data Interest Group, LANL, Feb 21st 2013 15 [Unclassified]
- 16. Approach 1: Implementation • Python • MPI L • PyMPI LL • No failure detection, no auto restart, no zombie killing, no … LLL • Several months of experiments to find issues, fine tune parameters most likely to complete… Big Data Interest Group, LANL, Feb 21st 2013 16 [Unclassified]
- 17. Approach 2: No Interaction • 43 read/split nodes • Phase 1: Read nodes split CDX files to 3000 slices Big Data Interest Group, LANL, Feb 21st 2013 17 [Unclassified]
- 18. Approach 2: No Interaction • Phase 2a: Transfer CDX slices to Control node • Phase 2b: Transfer CDX slices to Write nodes Big Data Interest Group, LANL, Feb 21st 2013 18 [Unclassified]
- 19. Approach 2: No Interaction • 50 write nodes (* 60 slices each = 3000 slices) • Phase 3: Merge slices from nodes to BerkeleyDBs Big Data Interest Group, LANL, Feb 21st 2013 19 [Unclassified]
- 20. Next Steps • Re-index, using non-interactive approach • New data: 14 Tb (~120Tb uncompressed?) • Use FileMap for better automation? • Two eSata 8T LaCie cubes, 2 3T internal drives to install locally • More intelligent data partitioning • Some sort of error detection and handling! Big Data Interest Group, LANL, Feb 21st 2013 20 [Unclassified]
- 21. Memento http://mementoweb.org/ Robert Sanderson rsanderson@lanl.gov @azaroth42 Herbert Van de Sompel herbertv@lanl.gov @hvdsomp Big Data Interest Group, LANL, Feb 21st 2013 21 [Unclassified]