1. Chapter 10
Archives and Backups

2. Example Backup System

3. Why Backup? Types of failures
Power failures (software/hardware failure)
Natural disasters (fire, flood)
Security incidents (theft)
Hardware Failures (disk crash)
User error (rm -rf)
Social issues (stolen data)

4. Backup Best Practices Centralized backup location Label makers
Label everything!
Backup intervals
User accounts (daily)
Software development – Repositories (e.g. SVN)
At a minimum weekly
Make daily dumps fit on one piece of media
Keep media off-site
Protect your backups
Verify your media

5. A common backup strategy
“Do nothing”
It is the most widely used backup strategy.
No initial costs.
No backup schedule to follow
If you lose all your data – “Too bad so sad”
“Do nothing’” is the correct backup method for /usr/obj, /usr/src and other directory trees that can be exactly recreated by your system – but if in doubt, BACK IT UP!

6. Best Practices cont’ Backup data to fit on one piece of media
(realistic ?)
Keep backups off site?
(typical for larger corporations / sensitive media)
Protect backups
Physical security
Verify backup media
Generate catalog of backed up media
Remember the lifespan of recordable media (e.g. tapes)
Worst case mitigation

7. Backup Media Optical CD-R,DVD-R,Blu-Ray Max capacity 50GB (BD-R DL)
Interface
SATA
USB(2.0, 3.0)

8. Backup Media cont’ Removable Hard Drives Interface
USB
Firewire
Thunderbolt
Ideal for personal use/small systems

9. Backup Media cont’ Small Tape drives DAT – digital audio tape
DDS – digital data storage
160GB

10. Backup Media cont’ DLT/S-DLT digital linear tape
Higher capacities = higher $$$$
Qauntum
600GB

11. Backup Media cont’ AIT - Advanced Intelligent Tapes – 500GB?
VXA – 160GB?
LTO – Linear Tape Open
HP AJ038A Black 76.8TB Rack mount Fibre Channel Interface LTO Ultrium 4 StorageWorks MSL4048 Tape Library
$12K!!!!

12. My Sample Server

13. Linux Backup Tools Open Source options: dump tar
rsync (Apple’s Time Machine uses this)
Amanda
Bacula (heavily used, very popular)

14. DUMP Linux utility Creates backups that can span several tapes
Backups/restores any file type
Allows for incremental backups
Maintains file permissions, ownership, and modification times

15. DUMP cont Dump does not work across remote file systems
Dump only works on one disk partition
Dump is based on levels (0 to N)
A level N dump backs up all files that have changed since the last dump of level less than N
Level 0 puts entire file system on tape
The “restore” command will restore files archived by dump

16. Dump example
To make a backup for a directory or file : dump -0f tbackup /home/tavaris
This command creates a dump-file called “tbackup” which is the backup of /home/tavaris/data directory.
dump-level 0 (specifies full-backup)
To make a backup for a directory or file which is already backedup with dump level 0: dump -1f tbackup /home/tavaris/
dump level 1 (specifies incremental backup)

17. Tar f “filename appears after arguments” z “compress with gzip”
tar (1) (Tape Archive) dates back to Version 6 of AT&T UNIX (circa 1975). tar operates in cooperation with the file system; tar writes files and directories to tape or to a file.
Usage: tar [options] archive-file-name files-to-archive
c -"create archive".
v "verbose”
print all the filenames added or extracted from archive
f “filename appears after arguments”
z “compress with gzip”
M “multi-volume”
x “extract”
d “compare” use to verify backups
n “newer” for incremental backups

18. Examples using tar
Let's take a backup of /etc where most configuration files reside, and place it in /home/backups: # mkdir /home/backups # tar -cvf /home/backups/etc.tar /etc Remember: The -c option to tar tells it to create an archive, -v specifies verbose output and -f specifies the file to be either written to or read from. You'll see quite a lot of output as tar creates the archive at this point.

19. Examples using tar
Now we check whether our archive has actually been created # cd /home/backups # ls -al
This now show us a new file in this directory etc.tar
If we now wanted to view the contents of this backup we can run # tar -tvf etc.tar

20. Examples using tar
This will show you the contents of the etc directory as you backed it up.
To actually restore and and unpack the contents that were backed up previously: # cd /home/backups # tar -xvf etc.tar

21. Examples using tar
Notice that the restore actually creates a new directory etc where you are located – not in /etc !
This is because tar by default removes the leading '/' from the directories it has backed up in order not to overwrite the original files on your system when you choose to do a restore (a security consideration)

22. Tar Exercise Backup /etc directory to /home/student/backups/ cd
mkdir backups
tar –cvf /home/student/backups/etc.tar /etc
cd backups
View the contents that were backed up
tar –tvf etc.tar

23. Bacula Primer
Bacula is an open source set of applications for creating archives of filestysems and restoring file systems from archives
Enterprise level software
Can backup Unix, Linux, and Windows systems
Supports tape libraries, auto-changers, and multiple volumes
Creates a hash signature of file system
For file verification
And more!!!

24. Backups + Dracula = Bacula
It comes by night and sucks the vital essence from your computers!

25. Bacula Components

31. https://www. digitalocean