Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Booting and Shutdown
Shutting Down Systems
Chapter 5 527
that resulted from the improper shutdown. In nearly all cases, fsck can
find and fix all of the structural problems and the file system can then be
marked clean.
On rare occasions, the file system corruption is beyond what fsck can
automatically correct. In these cases fsck will terminate with an error
message indicating that you need to use it in an interactive mode to fix
the more serious problems. In these cases data loss is likely. Before using
fsck in interactive mode, try to back up any critical files by moving them
to another file system or backing them up to tape, if a back-up copy of
them does not already exist.
For a more detailed discussion of using fsck to repair file systems, refer
to the following manpages:
• fsck (1M)
• fsck_cachefs (1M)
• fsck_hfs (1M)
• fsck_vxfs (1M)
System Crashes / HP-UX Panics
Although rare, sometimes systems can shut themselves down
unexpectedly in an event known as a system crash or system panic. For a
detailed description of what to do if this happens, and an explanation of
what takes place following a system crash, see “Abnormal System
Shutdowns” on page 531.
Single-User Mode
A special operating mode, called single-user mode, is available on
HP-UX systems. While your system is in single-user mode only the
console is active, and a lot of the subsystems for HP-UX are not running.
This mode is usually used for system maintenance. There are two ways
to put your system into single-user mode:
1. Boot the system into single-user mode (for information on booting
Itanium Server systems into single-user mode see “Booting into
Single-User Mode” on page 483, or for information about booting
PA-RISC servers into single-user mode see“Booting into Single-User
Mode” on page 498).
2. Shut the system down into single-user mode from a higher running
mode (see “Normal (Planned) Shutdown” on page 522).