[心得] rsync備份系統以及grub重新安裝

[ringballer (.)]

原來的系統硬碟怪怪的，又有not start from physical sectors問題。
怕重新開機後開不了，以及想用新的分割，網路找到最佳方案似乎是用
rsync做系統移動。使用的OS是fedora21，以下是操作過程。

#Issue: some original OS SSD partitions do not start from physical sectors
and encounter failing probability. This may comes from direct system backup
using clonezilla from 256G SSD to 500G SSD
# Original SSD has 3 primary partitions, 1 extended partition, 1 logical
partition. New goal is to eliminate sector alignment issue and to
re-partition SSD


#Step A: partition new Disk
#Step A.1: make disk label as msdos
parted /dev/sdX mklabel msdos # (it seems gpt partition cannot work as
bootable device)

#Step A.2: partition new disk with parted.
#(This step could also be done with fdisk)
parted /dev/sdX mkpart primary 1M 1G  # creat /boot
parted /dev/sdX mkpart primary 1G 3G  # creat  swap
parted /dev/sdX mkpart primary 3G 99%  # creat /
parted /dev/sdX mkpart primary 99% 100% # creat /home

#Step A.3: assign bootable partition
parted /dev/sdX set 1 boot on    # make /dev/sdX1 bootable

Step A.4: format partitions and make swap
mkfs -t ext4 /dev/sdX1
mkswap       /dev/sdX2
mkfs -t ext4 /dev/sdX3
mkfs -t ext4 /dev/sdX4

#Step B: Assign Old UUIDs into new Disk
#Step B.1: Show All UUIDs
blkid

#Step B.2: Update All UUIDs in new Disk
tunefs2 -U Old_bootPartion_UUID   /dev/sdX1
mkswap  -U Old_swapPartition_UUID /dev/sdX2
tunefs2 -U Old_rootPartition_UUID /dev/sdX3
tunefs2 -U Old_homePartition_UUID /dev/sdX4

#Step C:mount new Disk partions in /mnt
mount /dev/sdX3 /mnt
mount /dev/sdX1 /mnt/boot
mount /dev/sdX4 /mnt/home

#Step D:synchronize all system. Sometimes /boot must be
synchronize seperately
rsync -aAxHAX --progress /
--exclude={"/dev/*","/proc/*","/sys/*","/tmp/*","/run/*","/mnt/*",
"/media/*","/lost+found"} /mnt

#Step E:grub install
#Step E.1: grub install in new disk. Without this step,
BIOS could not identify new Disk as bootable device
grub2-install --boot-directory=/mnt/boot /dev/sdX

#Step E.2 make grub configurations
for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /mnt$i; done
chroot /mnt
dracut -f #(Without this step, dracut could keep searching old disk
settings in booting process)
grub2-mkconfig -o /boot/grub2/grub.cfg
# after chroot /mnt, system regard /mnt/boot as /boot.

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推 ucrxzero: 為什麼不止備份資料碟就好
→ ucrxzero: 還要用dracut 跟grub粉麻煩
→ ringballer: 其實已經有分別用dd跟rsync備兩份到資料碟了
→ ringballer: dd還原是我惡搞不成後的最後手段
→ ringballer: 為了debug 跟bypass physical sector issue
→ ringballer: clonezilla我只好捨棄不用
→ ringballer: 最後採取這種繞了一大圈的rsync+grub install，在原系
→ ringballer: 統重開機前，把系統備份到新系統碟
※ 編輯: ringballer (150.116.204.152 臺灣), 03/04/2021 21:19:06
推 ucrxzero: bypass 是啥意思 壞掉的磁區直接改成\0ㄇ
→ ringballer: 在新系統碟用新partition裝舊系統而已
推 holishing: Fedora 21... 為什麼不乾脆直接用 CentOS 7 @@
→ holishing: 還是那是原本的系統XD
推 randy061: 這招會用，很多問題皆可解