update: safety first!
when it comes to important files: safety comes first
thus recommend to the user that wants to go pro the following backup system:
- have two complete backups at two different places:
- backupA: at the company, USB 3.0 (! THE MORE DATA IS BACKED UP THE MORE SPEED IS NEEDED (or restore might take DAYS!)) connected to the server, doing daily incremental backups
- backupB: being a fire-proof double-metal casing (EMP proof) vault at a different place (home?)
- change those backups every day if possible otherwise every week
- if ransomeware destroys backupA then in the worst case scenario, one day or one week of work is gone
- remember: whatever is physically connected to the server, can be encrypted by ransomeware
- have the backup strategy tested once a year
- where the backup is restored completely on a backup-server, to test if all data is there and how long the process takes (USB 2.0 is definitely a massive bottleneck)
find out what the drive you want to backup is called, in this case it’s an USB Stick /dev/sdb
you could use gparted which gives you a nice graphical view of where is what.
or you use:
lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 111.8G 0 disk |-sda1 8:1 0 107.2G 0 part / `-sda5 8:5 0 4.6G 0 part [SWAP] sdb 8:16 1 7.3G 0 disk `-sdb1 8:17 1 7.3G 0 part /media/usb0
mount | grep usb /dev/sdb1 on /media/usb0 type vfat (rw,nosuid,nodev,noexec,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=utf8,shortname=mixed,errors=remount-ro,user)
fill the device with zeros
should result in much smaler filesize of the backup (gzip compressed)
cd /media/usb0; # change to the dir your usb stick is mounted cat /dev/zero > bigfile.txt; # if it does not stop by itself "device full" then cancel it with Ctrl+C rm -rf bigfile.txt; # remove the big junk file again
dd does not do this automatically if you want to monitor the progress use pv
# install pv apt-get install pv; # the "manual way" # open a new terminal an fire up: kill -USR1 $(pgrep ^dd) # this will make dd report status information # in the terminal dd is currently running # loop while true; do kill -USR1 $(pgrep ^dd); sleep 1; clear; done
dd if=SOURCE of=TARGET
dd with gzip: TESTED and Worked!
!!! BE CAREFUL YOU DON’T WANT TO OVERWRITE ANY INTERNAL HARDDISK HERE!!!
this method was successfully tested in backing up and restoring an usb stick.
umount /dev/sdb; # umount the usb stick dd if=/dev/sdb | pv | gzip -c > /where/compressed/image/is/stored/USBStickImage.img.gz; # backup content of usb stick (inkluding boot sector) to a file
now unplug your current usb stick and insert new one…
gunzip -c /where/compressed/image/is/stored/USBStickImage.img.gz | pv | dd of=/dev/sdb; # restore content and boot sector to a different usb stick
dd if=/dev/sdb | pv | gzip -c > /mnt/DATA/SOFTWARE/ACRONIS/Acronis2015.bootstick.img.gz; # backup a 8GB Stick (resulted in 7.5GByte FILE!!! ARGH) gunzip -c /mnt/DATA/SOFTWARE/ACRONIS/Acronis2015.bootstick.img.gz | pv | dd of=/dev/sdb; # restore it to a 32GByte stick (takes a while)
i actually cacneled after 1.2GBytes…. Strg+C but the stick works! 😀
untested: dd with pigz (compression using multiple cores)
using multiple cores for compression speeds up image creation.
default block size to bs=1M is used for faster operation.
apt-get install pigz; # install pigz
create compressed backup file from whole disk with pigz
-0 = no compression
-6 = default compression (best speed/compression ratio)
-9 = maximum compression
dd bs=1M if=/dev/sdX | pigz -c6 > /path/backup_of_sdX.img.gz
restore compressed whole disk backup from file:
this will erase all the content of sdX
pigz -dc /path/backup_of_sdX.img.gz | dd bs=1M of=/dev/sdX
Look at partitions inside a raw image, find sector start and sector size:
fdisk -lu /path/backup_of_sdX.img.gz
Mount from image with sector start and sector size:
mount -o loop,offset=$((137216 * 512)) backup01.img /media/bkp1/
creditz thanks and src: https://designdesk.org/linux/dd-command-copy-whole-volumes
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