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

NOTE: A full backup does not mean a backup of every file on your system. It means
a backup of every file on your include list, regardless of when it was last backed up.
To ensure consistency, do not modify or use different graph files between full and
incremental backups.
Other backup utilities, such as tar, cpio, and pax, do not support the concept of
incremental backups, but can maintain timestamp data for files in the archives they
make. When using these utilities to restore files from archives, you can chose whether
to overwrite a newer file on disk with an older version of that file from an archive.
Backup Levels
A backup level is a level you define that identifies the different degrees of incremental
backups. Each backup level has a date associated with it that indicates when the last
backup at that level was created. You can have up to ten backup levels (0 through 9).
For example, level 0 is a full backup; level 1 backs up files that changed since the last
level 0 backup; level 2 backs up files that changed since the last level 1 backup, and so
on.
This brings up the question, “how does fbackup know when the previous backup
was created?” This information is contained in the file /var/adm/fbackupfiles/
dates, a file that is updated only when all of the following conditions are true:
• The -u option is used with fbackup.
• A graph file is used to indicate which files should be included/excluded when a
backup is performed.
• Neither the -i nor the -e option is used (graph file used instead).
• The backup completed successfully.
Backup levels are a way of specifying varying degrees of incremental backup. For
example, suppose you wanted to set up the following backup schedule:
• On the first day of the month, back up an entire set of selected files (a monthly,
full backup).
• Every Friday, back up all files in the selected set that have changed since the
previous Friday (a weekly, incremental backup so that you can back up and restore
files that have been active within the month, relatively quickly).
• Every day except Friday (or the first of the month), back up all of the files in the
selected set that have changed since the previous day (a daily, incremental backup,
so that you can quickly back up and restore files that have been active within the
last week).
There are three “layers” (levels) associated with the above schedule (the once per month
level, the once per week level, and the once per day level). The once per month level
is a full backup. The other two are incremental backups. The problem is how to
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