23.2 Methods of Backup and Restore

   

23.2 Methods of Backup and Restore

On HP-UX, you can use a number of methods for creating a backup and restoring data. However, data backed up with one method can't be restored with another method. Each of these methods has its own merits and demerits. On all types of UNIX systems, tar is the most widely used backup and restore method. However, HP-UX has a more-flexible mechanism that uses the fbackup and frecover commands. The common methods used for backup and restore are listed here.

  • fbackup/frecover

  • cpio

  • tar

  • dump/restore

  • vxdump/vxrestore

  • pax

While making a decision about which method should be used for a particular situation, consider the following criteria.

  • Is this method supported on other UNIX platforms?

  • Can it be used over a network?

  • Does the method support incremental backup?

  • How efficient is the method with tape utilization?

  • How easy is it to make file selections from many directories while creating the backup?

Depending on your environment, one or more of these criteria may be of more importance than others. For example, if you want to copy some files from HP-UX to some other UNIX system, you can't use fbackup . Similarly, if you want to create a backup of files larger than 2 GBytes, tar can't be used.

Comparison of Backup Methods

Table 23-1 shows a comparison of the two most widely used methods on HP-UX. These are the fbackup/frecover and tar methods. In the fbackup/frecover method, the fbackup command is used for backup, and the frecover command is used for restore. In the case of tar , the same command is used both for backup and restore using command line options.

Table 23-1. Comparison of Backup and Restore Methods
Feature fbackup/frecover tar
Supported on other UNIX platforms No Yes
Across the network use Yes Yes
Incremental backup supported Yes Can add new files at the end of an archive but is not a true multilevel backup method
Tape utilization Medium High
Backup of files larger than 2 GBytes Supported Not supported
Multiple backups on a single tape Not supported Supported
Verify backup Supported Not supported
Find a file on tape Possible, takes relatively less time Possible, takes relatively more time as all of the tape is searched
Across the file system backup Possible Possible
Ease of selecting files from different directories Relatively easy using graph files Possible but relatively difficult
Use of extended file attributes Possible Not possible

Using dd

The dd command is not a general-purpose backup method in the true sense. It is used to copy raw data from one place to another. For example, you can use the dd command to make an exact copy of a disk as it reads and copies data bit by bit. It may be useful to make a copy of a bootable disk.


   
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HP Certified
HP Certified: HP-UX System Administration
ISBN: 0130183741
EAN: 2147483647
Year: 2000
Pages: 390
Authors: Rafeeq Rehman

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