Ein paar Links dazu:

Datenbank:
http://books.google.com/books?q=High+Performance+MySQL

Wie skaliert digg.com:
- http://highscalability.com/digg-architecture
- http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9017778&pageNumber=1
- http://www.oreillynet.com/onlamp/blog/2006/04/digg_phps_scalability_and_perf.html

- http://danga.com/memcached/
- http://www.hibernate.org/414.html

Datenbanken generell:
http://awads.net/wp/2005/12/07/the-world-largest-database-runs-oracle/

Festplatte:

Filesystem v. Google:
Bigtable: A Distributed Storage System for Structured Data
http://labs.google.com/papers/bigtable.html

The Google File System
http://d.scribd.com/docs/2iajv9uxldete2xd4gdv.pdf

Generell skalierbar aufsetzen:
http://burnachurch.com/69/hochverfuegbare-linux-cluster/

DRBD ( mirroring a whole block device via (a dedicated) network )
http://www.drbd.org/