About Reliability, Availability, And Serviceability Features - Sun Microsystems Enterprise 250 Owner's Manual

About Reliability, Availability, and
Serviceability Features
Reliability, availability, and serviceability are aspects of a system's design that affect
its ability to operate continuously and minimize the time necessary to service the
system. Reliability refers to a system's ability to operate continuously without
failures and to maintain data integrity. System availability refers to the percentage of
time that a system remains accessible and usable. Serviceability relates to the time it
takes to restore a system to service following a system failure. Together, reliability,
availability, and serviceability provide for near continuous system operation.
To deliver high levels of reliability, availability and serviceability, the system offers
the following features:
Error correction and parity checking for improved data integrity
Easily accessible status indicators
Hot-pluggable disk drives
Support for RAID 0, 1, and 5 storage configurations
Environmental monitoring and fault protection
N+1 power supply redundancy
Hot-swappable power supplies
Automatic system recovery (ASR)
Hardware watchdog mechanism
Four different levels of system diagnostics
Remote System Control (RSC)
Error Correction and Parity Checking
Error correcting code (ECC) is used on all internal system data paths to ensure high
levels of data integrity. All data that moves between processors, I/O, and memory
have end-to-end ECC protection.
The system reports and logs correctable ECC errors. A correctable ECC error is any
single-bit error in a 64-bit field. Such errors are corrected as soon as they are
detected. The ECC implementation can also detect double-bit errors in the same
64-bit field and multiple-bit errors in the same nibble (4 bits).
40 Sun Enterprise 250 Server Owner's Guide • June 1998