Backups are one of the major tasks that a Systems Administrator do. We can use cpio, tar, ufsdump commands for this. All of these commands are useful, but ufsdump is though to be safe and complete. Here are few hints for the beginners.
You will have to replace the tape device name with the one you are using. See some scripts here.
If you are in hurry and want to use ufsdump and ufsrestore, see example below.
Using cpio
Using cpio to create a file archive on a tape device:
# find . -print |cpio -ocBv /dev/rmt0
Using cpio to list the entries in a file archive on a tape device:
# cpio -itcvB < /dev/rmt0
Using cpio to retrieve a file from a tape device:
# cpio -icvdBum file.name < /dev/rmt0
You can also use cpio to copy directory structure. For example copy
Directory structure from current path to /export/home/tariq
# find . -print|cpio -pmdv /export/home/tariq
Using tar
Using tar to create a file archive on a tape device:
# tar -cvf /dev/rmt0 file.name
or
# tar -cvf /dev/rmt0 .
or for multiple directory hierarchies
# tar -crvf my.tar `find /tmp/junk -type f` `find /var/tmp -type f`
using tar to list the entries in a file archive on a tape device:
# tar -tvf /dev/rmt0
using tar to retrieve a file from a tape device:
# tar -xvf /dev/rmt0 file.name
there is more than one way to skin these cats, this being no comprehensive
look at these utilities.
Using ufsdump and ufsrestore
ufsdump ( in other o/s called dump )is said to be the most reliable
way to backup the whole filesystem. ufsrestore is the utility for restoring
data from a ufsdump. We can use restore interactively to restore certain files
or directories.
To make a dump of root filesystem on tape device /dev/nrsa0. Note
that this is a non-rewinding device. See example below.
# /usr/sbin/ufsdump 0f /dev/rmt/0cn /
To interactively restore a backup
# /usr/sbin/ufsrestore -xvf /dev/rmt/0cn
Every thing will be restored in current directory.
Using mt command with dump and restore
mt (magnetic tape manipulating program) is a very useful command
specialy if you are using dump and restore combination.
Following are some useful options of mt command.
# mt status Print status information about the tape unit.
# mt rewind Rewind the tape.
# mt erase Erase the tape.
# mt retension Re-tension the tape (one full wind forth and back.
# mt fsf 1 Forward space count by one file. One can be any number.
-f option can be used with mt to specify the different device. For
solaris /dev/rmt/0 is the default device.
# mt -f /dev/rmt/1n fsf 3
Example
If you are backing up three filesystems /, /var and /usr on a solaris
Box to a tape device:
# /usr/sbin/ufsdump 0uf /dev/rmt/0n /
# /usr/sbin/ufsdump 0uf /dev/rmt/0n /var
# /usr/sbin/ufsdump 0uf /dev/rmt/0n /usr
This will take three file spaces, one for each filesystem. Filesystem / will
be on file count 0 of tape and /var will be on file count 1 and /usr will be
on file space 2. Option 0 specify full backup,u will update the dump record in
/etc/dumpdates file and f to specify file or device. You can use following
command sequence to restore /var filesystem.
# mt status
This will show you the current status of tape. After the backup
on a non-rewinding device, tape will show file number 2
# mt rewind
This will rewind the tape to beginning.
# mt status
Tape will be on file count 0
# mt fsf 1
Tape will move to file count number 1 where /var is dumped.
# /usr/sbin/ufsrestore -xvf /dev/rmt/0n
/var will be restored in current. This will over-write the current contents.
Use /dev/rmt/0cn for compression, no rewind device.
Commands for remote tape backup
It is often neccesary to backup into a remote machine's tape drive. Here are the commands that can be used to achieve this. Execute this command on the machine you want to backup.
$ tar cvf - $DIRNAME | rsh $SYS dd of=$TAPEDEV
Substitute
$DIRNAME with the directory to backup,
$SYS with the machine name with the tape drive,
$TAPEDEV with the tape device.
Note: You must be able to rlogin into the remote machine without a password. To do this add the name of your local machine with your user name in the .rhost file in your home directory on the remote machine.
To retrieve the backed up info...
rsh $REM dd if=$TAPEDEV | tar xvf -
Now some small scripts
#!/bin/sh
tar -cvf my.tar $(for i in `cat list`
do
echo $i
done)
exit
The script below is backing up to tape using dump command. Logging date and all
the messages to a log file.
#!/bin/sh
#
echo "$DATE"backup.log
filenumber=`/usr/bin/mt stat|/usr/bin/grep "File Number"|/usr/bin/awk '{print $3}'`
echo "Backing up / to tape location: $filenumber"backup.log
/sbin/dump -0ua -f /dev/nrsa0 / &2backup.log
if [ $? -eq 0 ];then
echo "/ backup successful"$HOME/log/backup.log
fi
Copy files ( even complete filesystem) from remote to local system
|
Note: You must be able to rlogin into the remote machine without a password. To do this add the name of your local machine with your user name in the .rhost file in your home directory on the remote machine.
#!/bin/sh
#
# Copies files from Remote System to the local current directory
#
name=`basename $0`
if [ $# -ne 2 ];then
echo "Usage: $name "
exit
fi
system=$1
dir_to_cp=$2
rsh $system "cd $dir_to_cp; find . -print|cpio -ocB"|dd ibs=5k obs=5k|cpio -iducmvB