Categorized | Backup

Backup commands – usage and examples

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Backup commands – ufsdump, tar , cpio
Unix backup and restore can be done using unix commands ufsdump , tar ,
cpio . Though these commands may be sufficient for small setups in
order to take a enterprise backup you have to go in for some custom
backup and restore solutions like Symatic netbackup, EMC networker or
Amanda .
Any backup solution using these commands depends on the type of backup you
are taking and capability of the commands to fulfill the requirement . Following
paragraphs will give you an idea of commands , syntax and examples.

Features of ufsdump , tar , cpio

ufsdump
1. Used for complete file system backup .
2. It copies every thing from regular files in a file system to special character and block device files.
2. It can work on mounted or unmounted file systems.

tar:
1. Used for single or multiple files backup .
2. Can’t backup special character & block device files ( 0 byte files ).
3. Works only on mounted file system.

cpio:
1. Used for single or multiple files backup .
2. Can backup special character & block device files .
3. Works only on mounted file system.
4. Need a list of files to be backed up .
5. Preserve hard links and time stamps of the files .

Identifying the tape device in Solaris

dmesg | grep st

Checking the status of the tape drive

mt -f /dev/rmt/0 status

Backup restore and disk copy with ufsdump :

Backup file system using ufsdump
ufsdump 0cvf /dev/rmt/0 /dev/rdsk/c0t0d0s0
or
ufsdump 0cvf /dev/rmt/0 /usr

To restore a dump with ufsrestore

ufsrestore rvf /dev/rmt/0
ufsrestore in interactive mode allowing selection of individual files and 
directories using add , ls , cd , pwd and extract commands .
ufsrestore -i /dev/rmt/0

Making a copy of a disk slice using ufsdump

ufsdump 0f – /dev/rdsk/c0t0d0s7 |(cd /mnt/backup ;ufsrestore xf -)

Backup restore and disk copy with tar :


Backing up all files in a directory including subdirectories to a  tape device (/dev/rmt/0),

tar cvf /dev/rmt/0 *

Viewing a tar backup on a tape

tar tvf /dev/rmt/0

Extracting tar backup from the tape

tar xvf /dev/rmt/0
(Restoration will go to present directory or original backup path depending on
relative or absolute path names used for backup )

Backup restore and disk copy with tar :

Back up all the files in current directory to tape .

find . -depth -print | cpio -ovcB > /dev/rmt/0
cpio expects a list of files and find command provides the list , cpio has
to put these file on some destination and a > sign redirect these files to tape . This can be a file as well .

Viewing cpio files on a tape

cpio -ivtB < /dev/rmt/0

Restoring a cpio backup

cpio -ivcB < /dev/rmt/0

Compress/uncompress files :

You may have to compress the files before or after the backup and it can be done with following commands .
Compressing a file

compress -v file_name
gzip filename

To uncompress a file

uncompress file_name.Z
or
gunzip filename

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