HP-UX Reference (11i v1 05/09) - 1M System Administration Commands A-M (vol 3)

f
fbackup(1M) fbackup(1M)
NAME
fbackup - selectively back up files
SYNOPSIS
/usr/sbin/fbackup -f
device [-f device ] ... [
-0-9][-nsuvyAEl ][-i path ][-e path ]
[
-g graph ][-d path ][
-I path ][-V path ][-c config ]
/usr/sbin/fbackup -f
device [-f device ] ... [
-R restart ][-nsuvyAEl ][-d path ][-I path ]
[
-V path ][-c config ]
DESCRIPTION
fbackup combines features of dump and ftio to provide a flexible, high-speed file system backup
mechanism (see dump(1M) and ftio(1)).
fbackup
selectively transfers files to an output device. For each
file transferred, the file’s contents and all the relevant information necessary to restore it to an equivalent
state are copied to the output device. The output device can be a raw magnetic tape drive (for example, a
DLT tape drive), the standard output, a rewritable magneto-optical disk, or a file.
The selection of files to back up is done by explicitly specifying trees of files to be included or excluded from
an
fbackup session. The user can construct an arbitrary graph of files by using the -i
or -e options on
the command line, or by using the
-g option with a graph file. For backups being done on a regular basis,
the -g option provides an easier interface for controlling the backup graph. fbackup selects files in this
graph, and attempts to transfer them to the output device. The selectivity depends on the mode (full or
incremental) in which fbackup is being used.
When doing full backups, all files in the graph are selected. When doing incremental backups, only files in
the graph that have been modified since a previous backup of that graph are selected. If an incremental
backup is being done at level 4 and the -g option is used, the database file is searched for the most recent
previous backup at levels 0-3. If a file’s modification time is before the time when the last appropriate ses-
sion began and the i-node change time is before the time that same session ended, the file is not backed up.
All directories lying on the path to a file that qualifies for the incremental backup will also be on the backup
media, even if the directories do not qualify on their own status.
If fbackup is used for incremental backups, a database of past backups must be kept. fbackup main-
tains this data in the text file
/var/adm/fbackupfiles/dates
, by default. Note that the directory
/var/adm/fbackupfiles
must be created prior to the first time fbackup is used for incremental
backups. The
-d option can be used to specify an alternate database file. The user can specify to update
this file when an fbackup session completes successfully. Entries for each session are recorded on
separate pairs of lines. The following four items appear on the first line of each pair: the graph file name,
backup level, starting time, and ending time (both in time(2) format). The second line of each pair contains
the same two times, but in strftime(3C) format. These lines contain the local equivalent of
STARTED:, the
start time, the local equivalent of
ENDED:, and the ending time. These second lines serve only to make
the dates file more readable; fbackup does not use them. All fields are separated by white space. Graph
file names are compared character-by-character when checking the previous-backup database file to ascer-
tain when a previous session was run for that graph. Caution must be exercised to ensure that, for exam-
ple, graph and ./graph are not used to specify the same graph file because fbackup treats them as
two different graph files.
The general structure of an
fbackup volume is the same, no matter what type of device is used. There
are some small specific differences due to differing capabilities of devices. The general structure is as fol-
lows:
• reserved space for ASCII tape label (1024 bytes)
• fbackup volume header (2048 bytes)
• session index (size in field of volume header)
• data
Each file entry in the index contains the file size, the volume number and the pathname of the file. At the
beginning of every volume, fbackup assumes that all files not already backed up will fit on that volume,
an erroneous assumption for all but the last volume. Indices are accurate only for the previous volumes in
the same set. Hence, the index on the last volume may indicate that a file resides on that volume, but it
may not have actually been backed up (for example, if it was removed after the index was created, but
before fbackup attempted to back it up). The only index guaranteed to be correct in all cases is the on-
line index (-I option), which is produced after the last volume has been written.
Specific differences in the structure of fbackup volumes are listed below:
Section 1M−−214 Hewlett-Packard Company − 1 − HP-UX 11i Version 1: September 2005