在linux上克隆树莓派SD卡

Linux上可以用dd命令给SD卡做完整备份,把dd命令参数中的ifinput file)和ofoutput file)调换就可以把dd备份的文件恢复回SD卡上,但是要小心不能恢复到错误的磁盘上。

首先使用fdisk命令获得SD卡的device id

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fdisk -l

然后用dd命令制作一个磁盘镜像文件(修改下面命令中的/dev/sdb为你的实际SD卡对应的设备文件,即上一条命令fdisk -l中获取到的设备文件),

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dd bs=4M if=/dev/sdb of=image1-`date +%d%m%y`.img

或者用下面的命令可以将镜像文件直接压缩,

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dd bs=4M if=/dev/sdb | gzip > image1-`date +%d%m%y`.img.gz

整个过程要花费一些时间来完成。

备份完的镜像文件很大,和SD卡的实际大小是一样的,为了减小镜像文件的大小,可以用github上的一个叫PiShrink的脚本来完成这个过程。

Pishrink 是一个 bash 脚本,它可以自动缩小 pi 映像文件,然后在启动时将其调整为 SD 卡的最大大小。 这将更快的把映像文件恢复到 SD 卡上,映像文件也能更好地压缩。

PiShrink.sh

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#!/bin/bash

version="v0.1.2"

CURRENT_DIR=$(pwd)
SCRIPTNAME="${0##*/}"
LOGFILE=${CURRENT_DIR}/${SCRIPTNAME%.*}.log

function info() {
echo "$SCRIPTNAME: $1..."
}

function error() {
echo -n "$SCRIPTNAME: ERROR occured in line $1: "
shift
echo "$@"
}

function cleanup() {
if losetup "$loopback" &>/dev/null; then
losetup -d "$loopback"
fi
if [ "$debug" = true ]; then
local old_owner=$(stat -c %u:%g "$src")
chown "$old_owner" "$LOGFILE"
fi

}

function logVariables() {
if [ "$debug" = true ]; then
echo "Line $1" >> "$LOGFILE"
shift
local v var
for var in "$@"; do
eval "v=\$$var"
echo "$var: $v" >> "$LOGFILE"
done
fi
}

function checkFilesystem() {
info "Checking filesystem"
e2fsck -pf "$loopback"
(( $? < 4 )) && return

info "Filesystem error detected!"

info "Trying to recover corrupted filesystem"
e2fsck -y "$loopback"
(( $? < 4 )) && return

if [[ $repair == true ]]; then
info "Trying to recover corrupted filesystem - Phase 2"
e2fsck -fy -b 32768 "$loopback"
(( $? < 4 )) && return
fi
error $LINENO "Filesystem recoveries failed. Giving up..."
exit -9

}

help() {
local help
read -r -d '' help << EOM
Usage: $0 [-sdrpzh] imagefile.img [newimagefile.img]
-s: Don't expand filesystem when image is booted the first time
-d: Write debug messages in a debug log file
-r: Use advanced filesystem repair option if the normal one fails
-p: Remove logs, apt archives, dhcp leases and ssh hostkeys
-z: Gzip compress image after shrinking
EOM
echo "$help"
exit -1
}

usage() {
echo "Usage: $0 [-sdrpzh] imagefile.img [newimagefile.img]"
echo ""
echo " -s: Skip autoexpand"
echo " -d: Debug mode on"
echo " -r: Use advanced repair options"
echo " -p: Remove logs, apt archives, dhcp leases and ssh hostkeys"
echo " -z: Gzip compress image after shrinking"
echo " -h: display help text"
exit -1
}

should_skip_autoexpand=false
debug=false
repair=false
gzip_compress=false
prep=false

while getopts ":sdrpzh" opt; do
case "${opt}" in
s) should_skip_autoexpand=true ;;
d) debug=true;;
r) repair=true;;
p) prep=true;;
z) gzip_compress=true;;
h) help;;
*) usage ;;
esac
done
shift $((OPTIND-1))

if [ "$debug" = true ]; then
info "Creating log file $LOGFILE"
rm "$LOGFILE" &>/dev/null
exec 1> >(stdbuf -i0 -o0 -e0 tee -a "$LOGFILE" >&1)
exec 2> >(stdbuf -i0 -o0 -e0 tee -a "$LOGFILE" >&2)
fi

echo "${0##*/} $version"

#Args
src="$1"
img="$1"

#Usage checks
if [[ -z "$img" ]]; then
usage
fi
if [[ ! -f "$img" ]]; then
error $LINENO "$img is not a file..."
exit -2
fi
if (( EUID != 0 )); then
error $LINENO "You need to be running as root."
exit -3
fi

#Check that what we need is installed
for command in parted losetup tune2fs md5sum e2fsck resize2fs; do
command -v $command >/dev/null 2>&1
if (( $? != 0 )); then
error $LINENO "$command is not installed."
exit -4
fi
done

#Copy to new file if requested
if [ -n "$2" ]; then
info "Copying $1 to $2..."
cp --reflink=auto --sparse=always "$1" "$2"
if (( $? != 0 )); then
error $LINENO "Could not copy file..."
exit -5
fi
old_owner=$(stat -c %u:%g "$1")
chown "$old_owner" "$2"
img="$2"
fi

# cleanup at script exit
trap cleanup ERR EXIT

#Gather info
info "Gathering data"
beforesize=$(ls -lh "$img" | cut -d ' ' -f 5)
parted_output=$(parted -ms "$img" unit B print | tail -n 1)
partnum=$(echo "$parted_output" | cut -d ':' -f 1)
partstart=$(echo "$parted_output" | cut -d ':' -f 2 | tr -d 'B')
loopback=$(losetup -f --show -o "$partstart" "$img")
tune2fs_output=$(tune2fs -l "$loopback")
currentsize=$(echo "$tune2fs_output" | grep '^Block count:' | tr -d ' ' | cut -d ':' -f 2)
blocksize=$(echo "$tune2fs_output" | grep '^Block size:' | tr -d ' ' | cut -d ':' -f 2)

logVariables $LINENO tune2fs_output currentsize blocksize

#Check if we should make pi expand rootfs on next boot
if [ "$should_skip_autoexpand" = false ]; then
#Make pi expand rootfs on next boot
mountdir=$(mktemp -d)
mount "$loopback" "$mountdir"

if [ "$(md5sum "$mountdir/etc/rc.local" | cut -d ' ' -f 1)" != "0542054e9ff2d2e0507ea1ffe7d4fc87" ]; then
echo "Creating new /etc/rc.local"
mv "$mountdir/etc/rc.local" "$mountdir/etc/rc.local.bak"
#####Do not touch the following lines#####
cat <<\EOF1 > "$mountdir/etc/rc.local"
#!/bin/bash
do_expand_rootfs() {
ROOT_PART=$(mount | sed -n 's|^/dev/\(.*\) on / .*|\1|p')
PART_NUM=${ROOT_PART#mmcblk0p}
if [ "$PART_NUM" = "$ROOT_PART" ]; then
echo "$ROOT_PART is not an SD card. Don't know how to expand"
return 0
fi
# Get the starting offset of the root partition
PART_START=$(parted /dev/mmcblk0 -ms unit s p | grep "^${PART_NUM}" | cut -f 2 -d: | sed 's/[^0-9]//g')
[ "$PART_START" ] || return 1
# Return value will likely be error for fdisk as it fails to reload the
# partition table because the root fs is mounted
fdisk /dev/mmcblk0 <<EOF
p
d
$PART_NUM
n
p
$PART_NUM
$PART_START
p
w
EOF
cat <<EOF > /etc/rc.local &&
#!/bin/sh
echo "Expanding /dev/$ROOT_PART"
resize2fs /dev/$ROOT_PART
rm -f /etc/rc.local; cp -f /etc/rc.local.bak /etc/rc.local; /etc/rc.local
EOF
reboot
exit
}
raspi_config_expand() {
/usr/bin/env raspi-config --expand-rootfs
if [[ $? != 0 ]]; then
return -1
else
rm -f /etc/rc.local; cp -f /etc/rc.local.bak /etc/rc.local; /etc/rc.local
reboot
exit
fi
}
raspi_config_expand
echo "WARNING: Using backup expand..."
sleep 5
do_expand_rootfs
echo "ERROR: Expanding failed..."
sleep 5
rm -f /etc/rc.local; cp -f /etc/rc.local.bak /etc/rc.local; /etc/rc.local
exit 0
EOF1
#####End no touch zone#####
chmod +x "$mountdir/etc/rc.local"
fi
umount "$mountdir"
else
echo "Skipping autoexpanding process..."
fi

if [[ $prep == true ]]; then
info "Syspreping: Removing logs, apt archives, dhcp leases and ssh hostkeys"
mountdir=$(mktemp -d)
mount "$loopback" "$mountdir"
rm -rf "$mountdir/var/cache/apt/archives/*" "$mountdir/var/lib/dhcpcd5/*" "$mountdir/var/log/*" "$mountdir/var/tmp/*" "$mountdir/tmp/*" "$mountdir/etc/ssh/*_host_*"
umount "$mountdir"
fi


#Make sure filesystem is ok
checkFilesystem

if ! minsize=$(resize2fs -P "$loopback"); then
rc=$?
error $LINENO "resize2fs failed with rc $rc"
exit -10
fi
minsize=$(cut -d ':' -f 2 <<< "$minsize" | tr -d ' ')
logVariables $LINENO minsize
if [[ $currentsize -eq $minsize ]]; then
error $LINENO "Image already shrunk to smallest size"
exit -11
fi

#Add some free space to the end of the filesystem
extra_space=$(($currentsize - $minsize))
logVariables $LINENO extra_space
for space in 5000 1000 100; do
if [[ $extra_space -gt $space ]]; then
minsize=$(($minsize + $space))
break
fi
done
logVariables $LINENO minsize

#Shrink filesystem
info "Shrinking filesystem"
resize2fs -p "$loopback" $minsize
if [[ $? != 0 ]]; then
error $LINENO "resize2fs failed"
mount "$loopback" "$mountdir"
mv "$mountdir/etc/rc.local.bak" "$mountdir/etc/rc.local"
umount "$mountdir"
losetup -d "$loopback"
exit -12
fi
sleep 1

#Shrink partition
partnewsize=$(($minsize * $blocksize))
newpartend=$(($partstart + $partnewsize))
logVariables $LINENO partnewsize newpartend
if ! parted -s -a minimal "$img" rm "$partnum"; then
rc=$?
error $LINENO "parted failed with rc $rc"
exit -13
fi

if ! parted -s "$img" unit B mkpart primary "$partstart" "$newpartend"; then
rc=$?
error $LINENO "parted failed with rc $rc"
exit -14
fi

#Truncate the file
info "Shrinking image"
if ! endresult=$(parted -ms "$img" unit B print free); then
rc=$?
error $LINENO "parted failed with rc $rc"
exit -15
fi

endresult=$(tail -1 <<< "$endresult" | cut -d ':' -f 2 | tr -d 'B')
logVariables $LINENO endresult
if ! truncate -s "$endresult" "$img"; then
rc=$?
error $LINENO "trunate failed with rc $rc"
exit -16
fi

if [[ $gzip_compress == true ]]; then
info "Gzipping the shrunk image"
if [[ ! $(gzip -f9 "$img") ]]; then
img=$img.gz
fi
fi

aftersize=$(ls -lh "$img" | cut -d ' ' -f 5)
logVariables $LINENO aftersize

info "Shrunk $img from $beforesize to $aftersize"

用法

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sudo pishrink.sh [-sdrzh] imagefile.img [newimagefile.img]
-s: Skip autoexpand
-d: Debug mode on
-r: Use advanced repair options
-z: Gzip compress image after shrinking
-h: display help text

如果指定了newimagefile.img参数,脚本会创建一个imagefile.img的拷贝,并且所有操作都会在这个拷贝上进行,这时需要你有足够的空间为imagefile.img做一个完整的拷贝。

  • -s 跳过自动扩展部分操作。
  • -d 创建一个名为 pishrink.log的日志文件,便于排错。
  • -r 尝试修复文件系统。
  • -zshrinking后使用gzip压缩镜像文件,生成的文件后缀为 .gz

前置条件

脚本对NOOBS镜像不起作用,因为NOOBS 分区 和树莓派的不一样,希望PiShrink后续会增加对NOOBS的支持。

如果是在Ubuntu上运行脚本,你可以能会得到e2fsck相关的报错(out of datemetadata_csum),使用Ubuntu 16.10或者更高版本可以解决这个问题。

安装

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wget https://raw.githubusercontent.com/Drewsif/PiShrink/master/pishrink.sh
chmod +x pishrink.sh
sudo mv pishrink.sh /usr/local/bin

例子

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[user@localhost PiShrink]$ sudo pishrink.sh pi.img
e2fsck 1.42.9 (28-Dec-2013)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/loop1: 88262/1929536 files (0.2% non-contiguous), 842728/7717632 blocks
resize2fs 1.42.9 (28-Dec-2013)
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/loop1 to 773603 (4k) blocks.
Begin pass 2 (max = 100387)
Relocating blocks XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 236)
Scanning inode table XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 4 (max = 7348)
Updating inode references XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/loop1 is now 773603 blocks long.

执行完脚本后,pi.img文件从$30G$缩减到了$3.1G$。