Installation guide

4.6.4.4 Cleanly Unmount File Systems Before Changing Operating
System Versions
If a system crashes or goes down unexpectedly due to a loss of power or
other similar circumstances, AdvFS will perform recovery the next time that
the filesets that were mounted at the time of the crash are remounted after
rebooting. This recovery keeps the AdvFS metadata consistent and makes
use of the AdvFS log file.
Different versions of the operating system use different AdvFS log record
types. Therefore, it is important that AdvFS recovery be done on the same
version of the operating system that was running at the time of the crash.
For example, if your system is running Version 4.0F and the system crashes,
do not reboot using Version 3.2G since that version of AdvFS may not be
able to work with the log records that the Version 4.0F system put into the
log.
Therefore, if you want to reboot using a different version of the operating
system, make sure that any mounted AdvFS filesets are unmounted cleanly
before rebooting. In addition, if the system panicked or an AdvFS domain
was domain-panicked, it is best to reboot using the original version of the
operating system and run the /sbin/advfs/verify command to make
sure that the domain is not corrupted. If it is not, it is then safe to reboot
using a different version of the operating system and remount the filesets.
4.6.4.5 Running Verify on AdvFS File Systems
Use the AdvFS verify utility (/sbin/advfs/verify) to check the
consistency of the on-disk metadata in an AdvFS domain. This utility has
been enhanced to better detect certain potential problems. Compaq
recommends that you run the verify utility during your regular
maintenance schedule.
You should run the verify utility when an entire AdvFS domain is
scheduled to be offline, as no fileset in the domain can be mounted when you
run the verify utility. If you create a cron job, ensure that it executes the
appropriate commands to dismount the file systems.
You should also run the verify utility prior to doing an update installation.
4.6.4.6 The vdump Utility Requires Two kill Signals
Testing of AdvFS on a multiprocessor system showed that occasionally
(about 30 percent of the time) when a test suite was run, it would fail
because vdump processes would not respond to kill -9 signals. The
workaround is to send such a process a second kill -9 signal.
Base System Software Notes 4–37