HP Tru64 UNIX 4.x Appendix B, Electrostatic Discharge, Appendix C, Controller Specifications, Appendix D, Drive Arrays and Fault Tolerance, Appendix E

	Contents
European Union Notice ..................................................................................................	A-4
Japanese Notice ..............................................................................................................	A-5
Taiwanese Notice............................................................................................................	A-5
Battery Replacement Notice ...........................................................................................	A-6
Appendix B
Electrostatic Discharge
Appendix C
Controller Specifications
Appendix D
Drive Arrays and Fault Tolerance
What Is a Drive Array?...................................................................................................	D-1
Fault-Tolerance Methods................................................................................................	D-5
RAID 0—No Fault Tolerance ..................................................................................	D-5
RAID 1+0—Drive Mirroring...................................................................................	D-6
RAID 5—Distributed Data Guarding.......................................................................	D-7
RAID ADG—Advanced Data Guarding..................................................................	D-9
Comparison of RAID Methods ..............................................................................	D-10
Other Fault-Tolerance Options...............................................................................	D-11
Appendix E
Hard Drive Installation and Replacement
General Information About Hard Drive Failure .............................................................	E-1
Recognizing Drive Failure .......................................................................................	E-2
Compromised Fault Tolerance .................................................................................	E-4
Automatic Data Recovery ........................................................................................	E-5
General Aspects of Drive Replacement..........................................................................	E-6
Drive Failure During Rebuild ..................................................................................	E-8
Moving Drives and Arrays .............................................................................................	E-9
Upgrading Hard Drive Capacity ............................................................................	E-10
Expanding and Extending Capacity .......................................................................	E-11

HP Smart Array 641/642 Controller User Guide v