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

Administering a System: Booting and Shutdown
Shutting Down Systems
Chapter 5522
Types of Shutdown
There are various types of shutdown, both planned, and unplanned. This
section covers several common situations:
• A “Normal (Planned) Shutdown” on page 522
• “Power Failure” on page 525
• “System Crashes / HP-UX Panics” on page 527
• “Unclean Shutdowns” on page 526
Normal (Planned) Shutdown
Hopefully, most of your system shutdowns will be of this type. With a
normal shutdown, you have time to prepare the system and its users so
that the system can be restarted and work can continue with no loss of
data, and as little disruption as possible.
As mentioned in the overview to this section, it is important not to
simply turn off your computer (as you might be able to do with a personal
computer).
In order to maximize system performance, recently used data from disk
files is kept and updated in memory. Periodically (by default, every 30
seconds), a program called sync is run to make sure the file systems on
disk are kept up to date in the event of an unplanned shutdown (the
on-disk file systems are synchronized with the memory-based
changes). But, if it’s been 29 seconds since the last run of sync, there are
probably memory based changes that are not yet reflected on disk. If the
system crashes now, this can cause inconsistencies in file system
structures on disk (which, although not usually the case, can cause
corrupt files or loss of data).
Also, users of both your system and other systems in the network that
depend on your system for some resource will be affected. It is always
best to notify them in advance of any planned shutdown so that they can
plan for the shutdown and minimize the impact to their work.
The basic procedure for a planned shutdown of your system is:
Step 1. Notify anyone who is likely to be affected by the shutdown of your
system. You can do this by:
• e-mail