86 lines
1.9 KiB
Markdown
86 lines
1.9 KiB
Markdown
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---
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title: Backing up and restoring whole block devices
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date: 2015-02-14 08:30:51
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tags: [raspberry pi, hardware]
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---
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SD cards are not really a reliable storage, especially when used
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constantly e.g. while sitting in always powered-on Raspberry Pi. Because
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of that I've recently needed to perform lots of backup/restore
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operations ;) I wrote this script for backing up:
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```
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#!/bin/bash
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if [[ -z $1 ]]; then
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echo "usage: $0 device_to_clone"
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exit
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fi
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device=$1
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timestamp=`date +%Y%m%d`
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dest_file="/tmp/$timestamp.dd.xz"
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echo "about to clone $device to $dest_file"
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echo "ctrl-c or [enter]"
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read
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sudo umount $device?
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sudo umount $device
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sudo sync
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sudo pv -tpreb $device | dd bs=4M | pixz > $dest_file
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sudo sync
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```
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And this one for restoring:
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```
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#!/bin/bash
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if [[ -z $1 ]] || [[ -z $2 ]]; then
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echo "usage: $0 restore_file.xz device_to_restore_to"
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exit
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fi
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source_file=$1
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if [[ ! -f $source_file ]]; then
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echo "cannot open $source_file"
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exit
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fi
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device=$2
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echo "about to restore $source_file onto $device"
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echo "ctrl-c or [enter]"
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read
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sudo umount $device?
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sudo umount $device
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pv -tpreb $source_file | pixz -d | sudo dd bs=4M of=$device
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sudo sync
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sudo eject $device
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```
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Some of the more fun features include progressbars and making sure you've unmounted the
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device properly before ;) This also uses parallel threads to deflate the
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data, so the XZ compression should not be a bottleneck on any modern
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machine. The scripts above were used to backup and restore SD cards but
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will work for any block device, be it an external or internal disk
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drive, etc. usage example [remember to use the whole device, not just
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its partition as an argument]:
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```
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./backup_sdcard /dev/sdc
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about to clone /dev/sdc to /tmp/20150214.dd.xz
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ctrl-c or [enter]
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[sudo] password for cyryl:
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umount: /dev/sdc1: not mounted
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umount: /dev/sdc2: not mounted
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umount: /dev/sdc: not mounted
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19,6MiB 0:00:02 [9,72MiB/s] [> ] 0% ETA 0:52:26
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```
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