Backup and Recovery Concept on Linux

Backup & Recovery Concept on RHEL / CentOS 5.X&6.X
Backup:-Data Backup is the physical copying of data files to a removable  storage device that allows the data to be stored in another location.  When needed, an individual data file or an entire set of data files,  can be restored to a computer system.
    1)To copy data to alternate media 
    2)To prevent data loss 
Note: Only administrators can backup the data
Types of data:
      I) System generated data
      II) User generated data
Types of backup:
      1)Full backup
      2)Incremental backup
      3)Differential backup
1)Full backup :   complete backup of entire system
2)Incremental backup:  It includes all files that were changed since last backup. It always smaller than differential backup.
3)Differential backup:  It includes all the files that were changed since last full backup. As time increases since the last full backup the size of differential backup increases.
Commands for backup:
     1)tar (tape archieve)
     2)cpio (copy input/output)
1) tar:
Note:destination must be in .tar extension
-t=table of content
-x=extract to
To take backup
#tar -cvf
ex:tar -cvf passwd.tar /etc/passwd 
To list the content of tar file
#tar -tvf
ex:tar -tvf passwd.tar 
To extract content of file
#tar -xvf
ex:tar -xvf passwd.tar
To take backup along with zip
#tar -cvzf
Note:file name must be with an extension of .tar.gz
example : #tar -cvzf passwd.tar.gz /etc/passwd
To extract zip file
#tar -xvzf
example : #tar -xvzf passwd.tar.gz
2) cpio(copy input/output):
Backup using cpio:
#ls | cpio -ov >
example:ls -l | cpio -ov > sun
To extract:
#cpio -iv
example:cpio -iv sun
3) dump  : 
Backup using dump:
#dump -Ouf
example:dump -Ouf /media/ sun
To extract:
#restore -f
example:restore -f sun
Remote backup:
#rsync -avz -e ssh :
example:rsync -avz mahesh -e ssh
#scp -r :
example:scp -r mahesh

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