guide to linux installation and administration, 2e1 chapter 13 backing up system data
TRANSCRIPT
![Page 1: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/1.jpg)
Guide to Linux Installation and Administration, 2e 1
Chapter 13
Backing Up System Data
![Page 2: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/2.jpg)
Guide to Linux Installation and Administration, 2e 2
Objectives
In this chapter, you will:
• Understand data backup strategies
• Describe hardware and software used to back up Linux systems
• Use popular backup utilities such as tar, cpio, and graphical backup utilities
![Page 3: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/3.jpg)
Guide to Linux Installation and Administration, 2e 3
Understanding Backup Strategies
• A backup is a copy of data on a computer system
• A backup plan is a written document that outlines when, how, and why various files will be backed up, stored, and restored
• Backup media is the item that holds backed-up data
• To restore data is to copy it from backup media back to the file system where that data is normally used, and from which it was lost
![Page 4: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/4.jpg)
Guide to Linux Installation and Administration, 2e 4
Asking Initial Questions
• What files should be backed up?• Who will back up files?• Where are files located?• How should backups be performed?• Must you be able to restore data within a
specific period of time?
![Page 5: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/5.jpg)
Guide to Linux Installation and Administration, 2e 5
Determining the Value of Data
• A backup strategy should be based on the value of the data you are backing up
• The dollar value and time sensitivity of the data stored on your Linux systems determines how much expense you can justify in creating a backup plan
• The value of data includes several factors beyond the money paid to an employee to create the data
![Page 6: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/6.jpg)
Guide to Linux Installation and Administration, 2e 6
Determining When to Back up Data
• You can select a strategy based on how often data on your system changes and how valuable or critical each incremental piece of data is
• User data, log files, and e-mail archives change daily and are normally the focus of frequent backups
![Page 7: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/7.jpg)
Guide to Linux Installation and Administration, 2e 7
A Linux Backup Strategy
• A Linux backup strategy is based on the standard three-level backup method
• A multilevel backup system provides a reasonable trade-off between convenience and low cost on one side, and protecting data on the other
![Page 8: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/8.jpg)
Guide to Linux Installation and Administration, 2e 8
Using Backup Levels
• A backup level defines how much data is to be backed up in comparison with another backup level
• Level 0 is a full backup• A level 1 backup might be done once per week• A level 2 backup could then be done each day• Storing only files that have changed since a full
backup is called an incremental backup
![Page 9: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/9.jpg)
Guide to Linux Installation and Administration, 2e 9
Backup Levels
![Page 10: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/10.jpg)
Guide to Linux Installation and Administration, 2e 10
Restoring a File from a Three-Level Backup
• To locate a file you should follow the steps:– Check the most recent level 2 backup
– Check the most recent level 1 backup
– Check the most recent level 0 backup
![Page 11: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/11.jpg)
Guide to Linux Installation and Administration, 2e 11
Restoring Data from a Three-Level Set of Backup Media
![Page 12: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/12.jpg)
Guide to Linux Installation and Administration, 2e 12
Managing and Storing Backup Media
• You must determine how many backup media you will need (disks, tapes, cartridges) for each level
• The strategy for off-site storage depends on how critical data
![Page 13: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/13.jpg)
Guide to Linux Installation and Administration, 2e 13
Multiple Tapes Used for a Three-Level Backup Plan
![Page 14: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/14.jpg)
Guide to Linux Installation and Administration, 2e 14
Backing Up the Root File System
• Back up the root file system• Prepare to restore critical applications• Back up files:
– The kernel modules
– Configuration files
– File indexes
![Page 15: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/15.jpg)
Guide to Linux Installation and Administration, 2e 15
Hardware and Software Issues
• Linux includes all the necessary software utilities for many backup tasks
• Many different hardware devices are available for backing up data
![Page 16: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/16.jpg)
Guide to Linux Installation and Administration, 2e 16
Choosing Backup Media
• Storage space is measured according to its cost per megabyte or per gigabyte
• You normally have multiple copies of the data on your system, backed up at different times
![Page 17: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/17.jpg)
Guide to Linux Installation and Administration, 2e 17
Magnetic Media
• There are several types of magnetic media for backing up data:– RAID hard disks
– Floppy disks
– Removable magnetic media
– Removable hard disks
![Page 18: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/18.jpg)
Guide to Linux Installation and Administration, 2e 18
Optical Media
• Optical media include:– CDs
– DVD-RAM disks
• Standard CDs are a valuable method of exchanging data with suppliers and also of easily creating data archives
![Page 19: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/19.jpg)
Guide to Linux Installation and Administration, 2e 19
Tape Cartridges
• Tape cartridges continue to be the most popular and cost-effective backup media for most larger systems
• A jukebox is a backup device that holds multiple backup media (usually multiple tape cartridges) and can switch between them
• Tape drives are available in a variety of formats, each offering a different combination of cost, reliability, and data capacity
![Page 20: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/20.jpg)
Guide to Linux Installation and Administration, 2e 20
The Helical Scan Method is Used on 4mm and 8mm Tapes
![Page 21: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/21.jpg)
Guide to Linux Installation and Administration, 2e 21
Comparing Devices
• Different backup devices vary in speed, storage capacity, technologies used, availability, and cost, among other factors
• Legacy systems -computer systems that an organization already owns
• Many device specifications include the mean time between failures (MTBF)
![Page 22: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/22.jpg)
Guide to Linux Installation and Administration, 2e 22
Verification, Permissions, and Compression
• Backups should be verified regularly to be certain that data is recoverable from the backup media
• Verification includes following steps:– Pick a randomly selected backup file
– Check the file listing on the tape by querying for the contents of the backup media
– Restore a randomly selected file to the /tmp directory of your Linux system and compare with the original file
![Page 23: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/23.jpg)
Guide to Linux Installation and Administration, 2e 23
Verification, Permissions, and Compression
• File permissions must be part of a valid backup in order to avoid problems when files are restored
• Compression is commonly used when backing up data
• Compression increases vulnerability in case of corrupted data
![Page 24: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/24.jpg)
Guide to Linux Installation and Administration, 2e 24
Using Linux Backup Utilities
• The tar and cpio command-line utilities are commonly used for simple backups on every Linux system
• Popular commercial backup utilities include features:– Tracking tapes
– Keeping online indexes of each backup
– Automating schedules for unattended backup
![Page 25: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/25.jpg)
Guide to Linux Installation and Administration, 2e 25
Using tar and cpio
• Both tar and cpio can create archive files• tar and cpio can create an archive directly on a
tape cartridge or other backup device without first creating a file on your hard disk
• The tar command writes data to a filename or device that you provide
• The cpio command always writes data back to STDOUT
• The cpio and tar utilities are used in conjunction with the find command
![Page 26: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/26.jpg)
Guide to Linux Installation and Administration, 2e 26
Other Backup Utilities
• Many free and commercial utilities are available to help system administrators manage their backup strategy
• Most of these are graphical applications and include facilities for network-wide backup, managing large sets of backup media, and verifying or restoring files from backup media
![Page 27: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/27.jpg)
Guide to Linux Installation and Administration, 2e 27
Other Backup Utilities
• The kdat Tape Back-up Tool provides the following features:– Back up and restore files
– Verify tape contents
– Manage mounting/unmounting tape cartridges
– Manage tape indexes
– Format tapes
![Page 28: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/28.jpg)
Guide to Linux Installation and Administration, 2e 28
Other Backup Utilities
• Linux backup utilities are:– BRU
– Arkeia
– Storix
– Hypertape
– Replcator
– AMANDA
– Legato
![Page 29: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/29.jpg)
Guide to Linux Installation and Administration, 2e 29
The kdat Utility in KDE
![Page 30: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/30.jpg)
Guide to Linux Installation and Administration, 2e 30
Setting Preferences in kdat
![Page 31: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/31.jpg)
Guide to Linux Installation and Administration, 2e 31
The Arkeia Commercial Backup Program
![Page 32: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/32.jpg)
Guide to Linux Installation and Administration, 2e 32
Summary
• A backup plan helps a system administrator create an orderly system for backing up Linux data on a regular basis and restoring lost data as needed
• The dollar value and time sensitivity of the data determine the backup strategy
• A three-level backup method is commonly used• All data is backed up monthly (level 0), and
changed files are backed up weekly (level 1) and daily (level 2)
• Backing up the root file system and preparing to restore critical applications are parts of a backup plan that may require special attention
![Page 33: Guide to Linux Installation and Administration, 2e1 Chapter 13 Backing Up System Data](https://reader036.vdocuments.us/reader036/viewer/2022081506/56649d985503460f94a825a7/html5/thumbnails/33.jpg)
Guide to Linux Installation and Administration, 2e 33
Summary
• Magnetic and optical backup media are available, but tape cartridges continue to be the most popular and cost-effective backup media for most larger systems
• Backups should be verified regularly to be certain that data is recoverable from the backup media
• Backup systems vary in speed, storage capacity, technologies used, availability, and cost
• The tar and cpio are commonly used command-line backup utilities on Linux system
• Free and commercial graphical utilities are available to help system administrators manage their backup strategy