Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Managing Disks and Files

Backing Up Data

Chapter 6684

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 distinguish between the two

types of incremental backup. This is accomplished with backup levels.

The ﬁle /var/adm/fbackupfiles/dates contains information about

when the last backup at each backup level was performed. This

information is used by fbackup, along with the modiﬁcation date stamps

on the ﬁles themselves, to determine which ﬁles in the speciﬁed set are to

be included with the backup that is currently being created.

As previously stated, you can have up to 10 backup levels. When you run

fbackup, you can tell it which level to use. fbackup will use the level you

give it as follows:

• Level 0 is always considered a full backup

• Higher levels are generally used to perform incremental backups.

• When doing an incremental backup of a particular graph (speciﬁed

by a graph ﬁle name), at a particular level, fbackup will search the

ﬁle /var/adm/fbackupfiles/dates to ﬁnd the date of the most

recent backup of the same graph that was done at a lower level. If no

such entry is found, the beginning of time is assumed. All ﬁles in the

speciﬁed graph that have been modiﬁed since this date are backed up

Example of Setting Backup Levels

Assume you want the following three backup levels:

• Level 0 - full monthly backup

• Level 1 - weekly backup on Friday

• Level 2 - daily backup, except Friday

There are three ways you can implement these levels: use SAM, enter

the fbackup command and specify a backup level on the command line,

or automate the commands (see “Setting Up an Automated Backup

Schedule” on page 690). The ﬁgure below illustrates the level numbers

for implementing this example.

Date: 123456789101112131415...1

Day: Su MTWThFrSaSuMTWThFSaSu...

Backup level022221222222122...0