HP-UX System Administrator's Guide: Routine Management Tasks HP-UX 11i v3 (B3921-90023, September 2010)

— “Network Gateway” (page 89)

— “NFS File Server” (page 89)

— “NFS Client” (page 90)

• “Avoiding a Shutdown When Possible” (page 90)

For additional information on shutting down systems, see HP-UX System Administrator’s

Guide: Overview.

Types of Shutdown

There are various types of shutdown, both planned, and unplanned. This section covers

several common situations:

• A “Normal (Planned) Shutdown” (page 83)

• “Power Failure” (page 86)

• “System Crashes / HP-UX Panics” (page 88)

• “Unclean Shutdowns” (page 87)

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).

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:

Shutting Down Systems 83