Installation guide

user activity changes a file after the inode data is recorded, but before the
file is backed up, the backup may be corrupted.
To shut down the system, unmount a file system, and check the integrity of
a file system:
1. Shut down the system.
For example, to shut down the system in 5 minutes and give users
periodic warning messages, enter:
# /usr/sbin/shutdown +5 ’System going down to perform backups’
2. Use the umount command with the −a option to unmount the file
systems that you want to back up:
# /sbin/umount -a
Note that the root file system remains mounted.
3. Use the fsck command to ensure the integrity of the file system.
For example, to check a file system for an RZ57, unit 0, partition c,
enter:
# /sbin/fsck -o /dev/rz0c
This chapter describes a backup strategy that uses the dump and restore
group of backup commands. Other backup strategies are possible. For
example, you could use the find command to produce a list of files that
must be backed up and pipe the list to a backup program such as tar or
cpio. Refer to the find
(1), tar(1), and cpio(1) reference pages for more
information.
11.3.1 Choosing a Backup Schedule
When deciding how often to back up each file system, you should think
about the balance between the potential loss of user time and data and the
time it takes you to perform backups. Ask yourself the question, "How
much information can I afford to lose?" The answer will help you determine
your minimum backup interval. On most systems the backup interval is
daily, but you can choose any other interval.
It is not necessary to back up all the files in a file system at each backup.
Back up only those files that have changed since a previous backup; this is
called an incremental backup. Using the dump and restore commands,
you can perform up to nine levels of incremental backups. For example,
while a level 0 dump backs up an entire file system, a level 1 dump backs
up only those files since the last level 0 dump, and a level 7 dump backs up
only those files since the last lower level dump.
11–10 Administering the Archiving Services