Petabytes of Preservation on Tape Jason Pierson Oct 2012

Transcription

1 Petabytes of Preservation on Tape Jason Pierson Oct 2012

2 Today we will cover Preservation system overview Tape subsystem design considerations Tape subsystem architecture 2

3 What do we preserve and why? FamilySearch is all about family history, genealogy, and preserving records that document the human race and our relationships to each other Families are at the core of our beliefs FamilySearch.org is free to the public, with the goal of helping people find their ancestors Sponsored by The Church of Jesus Christ of Latter-Day Saints 3

4 Holistic View

5 Digital Pipeline Source Records Ingest Process Enhance Distribute Fixity Validation Field Cameras Disk Shuttles Image Conversion Indexing Web Microfilm Scanners Network Transfer Audit Waypoint Donor Copy Digital Born Manual Entry Normalize Describe Preservation 5

6 Digital Preservation System Tessella Safety Deposit Box Transfer Tape Oracle Server SDB Server JobQueue Servers Pres Facility Tape Ingest Worker FamilySearch Tape Storage Subsystem 6

7 Division of Labor SDB Core management Workflows Characterization Provenance Virtual AIP tracking Reporting Artifact catalog Tape Storage System Media inventory Physical artifact location Drive/media errors Artifact storage and retrieval Fixity validation Media refresh 7

8 Hardware Components Dell servers Oracle / StorageTek Tape Libraries SL ,000 tape capacity T10000C Tape drives aka T10KC 5 TB per cartridge On-drive fixity 8

9 Software Components Tessella Safety Deposit Box (SDB) Java Internally developed Java tape library toolkit Nagios IT monitoring Splunk Log mining and analysis AppDynamics Application monitoring Linux 9

10 Why Tape? <what Gary said > Longer media life Lower cost per PB over time Storage density Environmental condition resiliency High-speed writing throughput Greater bandwidth for transfers and migrations 10

11 Storage Design Considerations Scalability Loosely coupled architecture Handling of updated content Layout of files on one tape and across tapes Storage layer database design (tape inventory) Preservation planning Fixity design and validation Repository to repository migrations Tape subsystem monitoring 11

12 Volume Profile 15 TB of images generated daily 770 million J2K images x 2 copies 11,000 LTO-4 tapes (800 GB each) 30 TB additional daily processing capacity required for migration Targeting total system throughput of 50 TB per day 12

13 Writing to Tape 1 Pipeline 3 SDB 8 xfer Tape Tape Ingest Reader Tape Service Queue Staging Disk Tape Service 6 7 Archive Tape 13

14 File Layout on Tape Package file All images for a single collection XML descriptor files Package files are written out in 2 MB blocks ~ 3-4% slack space at end of each tape Package files not broken across tapes currently 14

15 Fixity Management Fixity values created at time of capture Provenance changes tracked for every conversion and new fixity is generated Three levels of fixity image file package file every 2 MB block Fixity can be checked at the drive level or the application level 15

16 Updating Content SDB tracks manifestations of each artifact as new versions are created AIPs are logical and can be spread across tapes over time Content is not deleted, but outdated content can be orphaned intentionally by de-referencing 16

17 Tape Database The tape storage subsystem maintains its own database, separate from SDB Physical tape location within library Location of collections Location of artifacts Media tracking (errors, usage, deploy date) Supports media refresh process Cross-references each entity with UUID 17

18 Tape Subsystem Monitoring Key features Tape drive errors Media errors Trending detection Vendors Oracle Hi-Stor 18

19 Repository to Repository Migration One-time migration Repository A Adapter Universal Migration Module Adapter Repository B 2-way Sync 19

20 2012 The Road Ahead Move SDB and tape subsystem to production 2013 Migrate current repository to SDB 2014 Move into new dedicated preservation facility 20

21 Don t hesitate to contact us for collaboration Jason Pierson jpierson@familysearch.org Thank you