Guiding ideas of the FACIT Guiding ideas of the FACIT Storage ArchitectureStorage Architecture

Library of Congress Storage Vendor Meeting

Sept 18, 2007Terry Moore, University of Tennessee, KnoxvilleLarry Carver, University of California at Santa

Barabara

What is FACITWhat is FACIT FACIT – Federated Archive

Cyberinfrastructure Testbed FACIT: project of National Geospatial Data

Archive (NDIIPP partner) Goal of FACIT: Create a testbed to test a

different approach to federated resource sharing, redundancy and access

FACIT partners: NGDA (UCSB and Stanford)Logistical Networking (UTK) – network storage techREDDnet (Vanderbilt) – NSF funded infrastructure

using LN for data intensive collaboration2

Typical design perspectiveTypical design perspective

3

recentcontent

now

takeaction

now

+

100 years

“The archive begins today”

FACIT design perspectiveFACIT design perspective

4

oldcontent

now - 50 now + 50now

takeaction

contentancientcontent

“mid-century perspective”

5

What archivist in the middle seesWhat archivist in the middle sees Repeated migrations across storage media and

storage systemspast and future – 20 to 30+ over a century

Repeated migrations across archive systemseach possibly necessitating transformation and

reorganization of archived content Repeated handoffs between institutions

each implementing different policies How can we create a “handoff process” that

can be sustained? Design for interoperability and deployment

scalability first How do you do that?

6

Generic storage stackGeneric storage stack

The common interface “virtualizes” the technology beneath itWhat interface goes here?

Issue: Whatever you choose will become the basis for storage interoperability for adopters

LN hypothesis: Do it the way that the network people did it

““Bits are bits” infrastructure for storageBits are bits” infrastructure for storage

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Standardize on what we have an adequate common model for Storage/buffer

management Coarse-grained data

transfer Leave everything else to

higher layers End-to-end services:

checksums, encryption, error encoding, etc.

Enable autonomy in wide area service creation: security, resource allocation, QoS guarantees…

Gain the benefits of interoperability today!

One infrastructure serves all

8

Basic elements of the LN stackBasic elements of the LN stack

Highly generic, “best effort” protocol for using storage

•Generic -> doesn’t restrict applications•“best effort”-> low burden on providers•Easy to port and deploy

Metadata container bit-level structure

•Modeled on Unix inode •bit-level structure, control keys, …•XML encoded

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Sample exNodesSample exNodes

A B C

0

300

200

100

IBP Depots

Network

Tennessee

UCSB Stanford

REDDnet

Crossing administrative domains, sharing resources

Question: Where is data object C?

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New federation members?New federation members?

• Add new depots

LoC

IBP Depots

Network

Tennessee

UCSB Stanford

REDDnet

• Rewrite the exNodes

• Copy the data

LN file downloadLN file download

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IBP Depots

exNode – 4 copies

TCP streams

LN file downloadLN file download

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REDDnet depot unit: COTSREDDnet depot unit: COTS

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• Dual core 2.4GHz AMD 64 X2 processors with 4GB of memory, • 4 x750GB SATA2 drives in hot-swap bays• Dual GigE NICs.  • OS stored on a USB-header mounted transflash drive; all disk drives available for use• >$700 per TB• “But there’s so much it doesn’t do!” True• Question: How much can we do in software on top? E.g. check-sums, error encoding, encryption, etc.