20240328-Debian12根分区扩容记录
title: Debian12根分区扩容记录
date: 2024/03/29
tags:
- Debian
- 扩容
categories: - 杂谈
[!WARNING]
以下操作可能会导致包括但不仅限于数据丢失、无法启动等问题，严重时您可能需要重装系统，如要继续，请确保已做好数据备份等准备工作。
Debian12根分区扩容记录
前言
情况是这样的，有一台Debian12的机器，磁盘分区信息如下：
root@xxx:~# df -Th
Filesystem Type Size Used Avail Use% Mounted on
udev devtmpfs 3.8G 0 3.8G 0% /dev
tmpfs tmpfs 775M 488K 775M 1% /run
/dev/vda1 ext4 19G 1.1G 17G 7% /
tmpfs tmpfs 3.8G 0 3.8G 0% /dev/shm
tmpfs tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs tmpfs 775M 0 775M 0% /run/user/0
可以看到根分区只有19G，但是呢现在有一块未使用的磁盘：
root@xxx:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sr0 11:0 1 368K 0 rom
vda 254:0 0 20G 0 disk
├─vda1 254:1 0 19G 0 part /
├─vda2 254:2 0 1K 0 part
└─vda5 254:5 0 975M 0 part [SWAP]
vdb 254:16 0 30G 0 disk
这块未使用的磁盘有30G，现在想把这30G加到根分区上去，思路就是采用LVM逻辑卷管理动态扩容，建立一个逻辑卷组，把vda和vdb都加入此卷组，达到物理上是两块不同磁盘，但逻辑上合并为一块磁盘的效果。
1.将磁盘vdb初始化为物理卷
root@xxx:~# pvcreate /dev/vdb
Physical volume "/dev/vdb" successfully created.
2.新建卷组并将vdb加入此卷组
root@xxx:~# vgcreate vg_root /dev/vdb
Volume group "vg_root" successfully created
3.在卷组中创建逻辑卷
root@xxx:~# lvcreate -l 100%FREE -n lv_root vg_root
WARNING: ext4 signature detected on /dev/vg_root/lv_root at offset 1080. Wipe it? [y/n]: y
Wiping ext4 signature on /dev/vg_root/lv_root.
Logical volume "lv_root" created.
可以使用lsblk命令查看vdb上已经创建了该逻辑卷：
root@xxx:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sr0 11:0 1 368K 0 rom
vda 254:0 0 20G 0 disk
├─vda1 254:1 0 19G 0 part /
├─vda2 254:2 0 1K 0 part
└─vda5 254:5 0 975M 0 part [SWAP]
vdb 254:16 0 30G 0 disk
└─vg_root-lv_root 253:0 0 30G 0 lvm
4.使用etx4文件系统格式化此逻辑卷
root@xxx:~# mkfs.ext4 /dev/vg_root/lv_root
mke2fs 1.47.0 (5-Feb-2023)
Creating filesystem with 7863296 4k blocks and 1966080 inodes
Filesystem UUID: 65808f9c-feec-4b53-a238-68afc9675bf2
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
5.修改/etc/fstab
首先使用blkid命令得到上面创建的逻辑卷的UUID：
root@xxx:~# blkid
/dev/vdb: UUID="yidW91-cpxx-fByR-WkMU-qX0R-mLXI-4rG0w5" TYPE="LVM2_member"
/dev/sr0: BLOCK_SIZE="2048" UUID="2024-03-28-20-15-38-00" LABEL="cidata" TYPE="iso9660"
/dev/mapper/vg_root-lv_root: UUID="65808f9c-feec-4b53-a238-68afc9675bf2" BLOCK_SIZE="4096" TYPE="ext4" # 这一项
/dev/vda5: UUID="63b700c5-f855-4754-a9ac-ce29e520ecf4" TYPE="swap" PARTUUID="1d6b09a9-05"
/dev/vda1: UUID="1038e8c5-a0e6-4031-aab4-c664d0bcf637" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="1d6b09a9-01"
示例：
原/etc/fstab内容如下：
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# systemd generates mount units based on this file, see systemd.mount(5).
# Please run 'systemctl daemon-reload' after making changes here.
#
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/vda1 during installation
UUID=1038e8c5-a0e6-4031-aab4-c664d0bcf637 / ext4 errors=remount-ro 0 1
# swap was on /dev/vda5 during installation
UUID=63b700c5-f855-4754-a9ac-ce29e520ecf4 none swap sw 0 0
/dev/sr0 /media/cdrom0 udf,iso9660 user,noauto 0 0
替换/etc/fstab中的根目录挂载项的UUID为上方逻辑卷的UUID，更改完成后如下：
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# systemd generates mount units based on this file, see systemd.mount(5).
# Please run 'systemctl daemon-reload' after making changes here.
#
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/vda1 during installation
UUID=65808f9c-feec-4b53-a238-68afc9675bf2 / ext4 errors=remount-ro 0 1
# swap was on /dev/vda5 during installation
UUID=63b700c5-f855-4754-a9ac-ce29e520ecf4 none swap sw 0 0
/dev/sr0 /media/cdrom0 udf,iso9660 user,noauto 0 0
6.挂载此逻辑卷并将原根目录同步到此卷
root@xxx:~# mount /dev/mapper/vg_root-lv_root /mnt
root@xxx:~# rsync -axHAWX --numeric-ids --info=progress2 / /mnt
1,086,763,736 99% 51.43MB/s 0:00:20 (xfr#18943, to-chk=0/24170)
7.绑定一些必要的系统目录和文件
root@xxx:~# mount --types proc /proc /mnt/proc
root@xxx:~# mount --rbind /sys /mnt/sys
root@xxx:~# mount --make-rslave /mnt/sys
root@xxx:~# mount --rbind /dev /mnt/dev
root@xxx:~# mount --make-rslave /mnt/dev
root@xxx:~# mount --rbind /run /mnt/run
root@xxx:~# mount --bind /etc/resolv.conf /mnt/etc/resolv.conf
8.chroot到新的根目录并更新grub和initramfs
root@xxx:~# chroot /mnt
root@xxx:/# grub-install /dev/vda
Installing for i386-pc platform.
Installation finished. No error reported.
root@xxx:/# update-grub
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-6.1.0-18-amd64
Found initrd image: /boot/initrd.img-6.1.0-18-amd64
Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.
done
root@xxx:/# update-initramfs -u -k all
update-initramfs: Generating /boot/initrd.img-6.1.0-18-amd64
9.退出chroot并重启
root@xxx:/# exit
exit
root@xxx:~# umount -l /mnt/sys # 卸载之前的挂载点，下同
root@xxx:~# umount -l /mnt/proc
root@xxx:~# umount -l /mnt/dev
root@xxx:~# umount -l /mnt/run
root@xxx:~# reboot
10.扩容新的根分区
重启完成之后，应该能看到上面新建的逻辑分区被挂载到了根目录：
root@xxx:~# df -Th
Filesystem Type Size Used Avail Use% Mounted on
udev devtmpfs 3.8G 0 3.8G 0% /dev
tmpfs tmpfs 775M 8.5M 767M 2% /run
/dev/mapper/vg_root-lv_root ext4 30G 1.1G 27G 4% /
tmpfs tmpfs 3.8G 0 3.8G 0% /dev/shm
tmpfs tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs tmpfs 775M 0 775M 0% /run/user/0
root@xxx:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sr0 11:0 1 368K 0 rom
vda 254:0 0 20G 0 disk
├─vda1 254:1 0 19G 0 part
├─vda2 254:2 0 1K 0 part
└─vda5 254:5 0 975M 0 part
vdb 254:16 0 30G 0 disk
└─vg_root-lv_root 253:0 0 30G 0 lvm /
接下来把原根分区所在的vda1也加入卷组vg_root：
root@xxx:~# pvcreate /dev/vda1
WARNING: ext4 signature detected on /dev/vda1 at offset 1080. Wipe it? [y/n]: y
Wiping ext4 signature on /dev/vda1.
Physical volume "/dev/vda1" successfully created.
root@xxx:~# vgextend vg_root /dev/vda1
Volume group "vg_root" successfully extended
root@xxx:~# lvextend -l +100%FREE /dev/vg_root/lv_root
Size of logical volume vg_root/lv_root changed from <30.00 GiB (7679 extents) to <49.04 GiB (12554 extents).
Logical volume vg_root/lv_root successfully resized.
root@xxx:~# resize2fs /dev/vg_root/lv_root
resize2fs 1.47.0 (5-Feb-2023)
Filesystem at /dev/vg_root/lv_root is mounted on /; on-line resizing required
old_desc_blocks = 4, new_desc_blocks = 7
The filesystem on /dev/vg_root/lv_root is now 12855296 (4k) blocks long.
注意：此时看一下/etc/fstab，确保和上面修改过的一致，再次执行：
grub-install /dev/vda
update-grub
update-initramfs -u -k all
完成之后再次重启，如果能正确引导且磁盘已扩容就大功告成：
root@xxx:~# df -Th
Filesystem Type Size Used Avail Use% Mounted on
udev devtmpfs 3.8G 0 3.8G 0% /dev
tmpfs tmpfs 775M 500K 775M 1% /run
/dev/mapper/vg_root-lv_root ext4 49G 1.4G 45G 3% /
tmpfs tmpfs 3.8G 0 3.8G 0% /dev/shm
tmpfs tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs tmpfs 775M 0 775M 0% /run/user/0
11.可能遇到的问题&解决方法
root@xxx:~# pvcreate /dev/vdb
Can't initialize physical volume "/dev/vdb" of volume group "vg_root" without -ff
/dev/vdb: physical volume not initialized.
root@xxx:~# pvs
WARNING: Couldn't find device with uuid BUVBX6-jfV5-cwDm-WVcM-YJdv-6oP7-peBjUu.
WARNING: VG vg_root is missing PV BUVBX6-jfV5-cwDm-WVcM-YJdv-6oP7-peBjUu (last written to /dev/vda1).
PV VG Fmt Attr PSize PFree
/dev/vdb vg_root lvm2 a-- <30.00g 0
[unknown] vg_root lvm2 a-m 19.04g 0
root@xxx:~# lvs
WARNING: Couldn't find device with uuid BUVBX6-jfV5-cwDm-WVcM-YJdv-6oP7-peBjUu.
WARNING: VG vg_root is missing PV BUVBX6-jfV5-cwDm-WVcM-YJdv-6oP7-peBjUu (last written to /dev/vda1).
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
lv_root vg_root -wi-----p- <49.04g
root@xxx:~# vgs
WARNING: Couldn't find device with uuid BUVBX6-jfV5-cwDm-WVcM-YJdv-6oP7-peBjUu.
WARNING: VG vg_root is missing PV BUVBX6-jfV5-cwDm-WVcM-YJdv-6oP7-peBjUu (last written to /dev/vda1).
VG #PV #LV #SN Attr VSize VFree
vg_root 2 1 0 wz-pn- <49.04g 0
root@xxx:~# df -Th
Filesystem Type Size Used Avail Use% Mounted on
udev devtmpfs 3.8G 0 3.8G 0% /dev
tmpfs tmpfs 775M 500K 775M 1% /run
/dev/vda1 ext4 19G 1.1G 17G 7% /
tmpfs tmpfs 3.8G 0 3.8G 0% /dev/shm
tmpfs tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs tmpfs 775M 0 775M 0% /run/user/0
解决方式：
# 确保当前根目录处于vda上
# 删除以上损坏的卷和卷组
vgchange -an vg_root # 禁用此卷组
vgreduce --removemissing vg_root # 删除卷组中的已丢失的卷
lvremove /dev/vg_root # 删除此卷组上的逻辑卷
vgremove vg_root # 删除此卷组
pvremove [--force --force] /dev/vdb # [强制]删除此物理卷（添加两个--force选项来强制删除）
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