The Red Hat Package Manager web site: http://www.rpm.org/.
Maximum RPM, by Ed Bailey (Red Hat Press).
"RPM-HOWTO," by Donnie Barnes: http://www.rpm.org/support/RPM-HOWTO.html.
http://www.cvshome.org/ is the home of the CVS project and includes a plethora of documentation. Of special interest is the Cederqvist, the official CVS manual, available at http://www.cvshome.org/docs/manual/.
Open Source Development with CVS, by Karl Fogel (Coriolis, Inc.). Most of the book is available online at http://cvsbook.red-bean.com/.
CVS Quick Reference Card: http://www.refcards.com/about/cvs.html.
Recall, an open source library for writing distributed, fault-tolerant, replicated storage servers. A Recall-based server will allow you to save and access data even in the presence of machine failures. See http://www.fault-tolerant.org/recall/.
Chapters 2, 4, 9, 11, and 28 in UNIX System Administration Handbook, by Evi Nemeth, Garth Snyder, Scott Seebass, and Trent H. Hein (Prentice Hall).
Chapters 4 and 5 in Optimizing UNIX for Performance, by Amir H. Majidimehr (Prentice Hall).
A good starting point is one of the classic textbooks used in operating system courses. For example:
Operating System Concepts, by Abraham Silberschatz and Peter Baer Galvin (John Wiley & Sons, Inc.).
Applied Operating System Concepts, by Abraham Silberschatz, Peter Baer Galvin, and Greg Gagne (John Wiley & Sons, Inc.).
Design of the Unix Operating System, by Maurice Bach (Prentice Hall).
The Memory Management Reference at http://www.xanalys.com/software_tools/mm/ is also very helpful.
The Heartbeat project is a part of the HA Linux project.
lbnamed, a load-balancing name server written in Perl: http://www.stanford.edu/~riepel/lbnamed/ or http://www.stanford.edu/~schemers/docs/lbnamed/lbnamed.html.
"Network Address Translation and Networks: Virtual Servers (Load Balancing)": http://www.suse.de/~mha/linux-ip-nat/diplom/node4.html#SECTION00043100000000000000.
"Efficient Support for P-HTTP in Cluster-Based Web Servers," by Mohit Aron and Willy Zwaenepoel, in Proceedings of the USENIX 1999 Annual Technical Conference, Monterey, CA, June 1999: http://www.cs.rice.edu/~druschel/usenix99lard.ps.gz or http://www.usenix.org/publications/library/proceedings/usenix99/full_papers/aron/aron_html/.
Perl modules available from http://www.modperl.com/book/source (not on CPAN):
Apache::BlockAgent, which allows you to block impolite web agents.
Apache::SpeedLimit, which allows you to limit indexing robots' speed.