Hetzner 使用 LVM 合并硬盘空间
Nov 25, 2021
由于原始硬盘容量无法满足业务需求，遂额外加购硬盘。起初使用的是 RAID0 方案合并硬盘空间，但是由于 RAID0 的特性限制，最终可用容量为最小硬盘容量乘以总硬盘数。如果硬盘大小不同则不可避免有大量的容量浪费。且 RAID0 本身有高风险，如果一枚硬盘物理损坏则全部数据丢失，无法找回。
开干
前往 Rescue System, 删除 RAID 并格式化盘符
mdadm --remove /dev/md0
mdadm --remove /dev/md1
mdadm --remove /dev/md2
mdadm --stop /dev/md0
mdadm --stop /dev/md1
mdadm --stop /dev/md2
mkfs.ext4 /dev/nvme0n1
mkfs.ext4 /dev/nvme1n1
mkfs.ext4 /dev/nvme2n1
通过 installimage 安装操作系统。在安装配置文件中修改和添加分区信息
...
SWRAID 0 ## 关闭 RAID
...
## 编写分区
PART /boot ext3 512M
PART lvm vg0 all
LV vg0 swap swap swap 32G
LV vg0 root / ext4 all
进入正常系统后，列出本机中的物理硬盘，记录硬盘名
fdisk -l
Disk /dev/nvme0n1: 1.86 TiB, 2048408248320 bytes, 4000797360 sectors
Disk model: SAMSUNG MZVL22T0HBLB-00B00
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xacf2949f
Device Boot Start End Sectors Size Id Type
/dev/nvme0n1p1 2048 1050623 1048576 512M 83 Linux
/dev/nvme0n1p2 1050624 4000795311 3999744688 1.9T 8e Linux LVM
Disk /dev/nvme1n1: 476.94 GiB, 512110190592 bytes, 1000215216 sectors
Disk model: SAMSUNG MZVLB512HBJQ-00000
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/nvme2n1: 476.94 GiB, 512110190592 bytes, 1000215216 sectors
Disk model: SAMSUNG MZVLB512HBJQ-00000
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/vg0-swap: 32 GiB, 34359738368 bytes, 67108864 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/vg0-root: 1.83 TiB, 2013504995328 bytes, 3932626944 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
添加其他物理卷至 LVM
pvcreate /dev/nvme1n1 /dev/nvme2n1
将其他物理卷扩展至卷组 vg0
vgextend vg0 /dev/nvme1n1 /dev/nvme2n1
将剩余空间添加至逻辑卷并整理
lvextend -l +100%FREE /dev/mapper/vg0-root
resize2fs /dev/mapper/vg0-root
查询可用空间
df -hl
Filesystem Size Used Avail Use% Mounted on
tmpfs 6.3G 940K 6.3G 1% /run
/dev/mapper/vg0-root 2.8T 1.9G 2.6T 1% /
tmpfs 32G 0 32G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
/dev/nvme0n1p1 488M 89M 374M 20% /boot
tmpfs 6.3G 0 6.3G 0% /run/user/0
fdisk -l
Disk /dev/nvme0n1: 1.86 TiB, 2048408248320 bytes, 4000797360 sectors
Disk model: SAMSUNG MZVL22T0HBLB-00B00
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xacf2949f
Device Boot Start End Sectors Size Id Type
/dev/nvme0n1p1 2048 1050623 1048576 512M 83 Linux
/dev/nvme0n1p2 1050624 4000795311 3999744688 1.9T 8e Linux LVM
Disk /dev/nvme1n1: 476.94 GiB, 512110190592 bytes, 1000215216 sectors
Disk model: SAMSUNG MZVLB512HBJQ-00000
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/nvme2n1: 476.94 GiB, 512110190592 bytes, 1000215216 sectors
Disk model: SAMSUNG MZVLB512HBJQ-00000
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/vg0-swap: 32 GiB, 34359738368 bytes, 67108864 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/vg0-root: 2.76 TiB, 3037720477696 bytes, 5933047808 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Bingo! 🎉
最后吐槽一下，中文互联网信息质量是真的烂。在中文互联网搜索技术资料，基本除了漫天飞舞的垃圾广告，剩下就是你抄我我抄你的垃圾社区“博客”和采集站，真正有意义的内容少之又少。这是我第一次处理 LVM 的问题，折腾花了不少时间，最终还是在某个英文网站上找到了参考资料；当然也有可能是我的中文搜索水平太烂。总之，务必学好英文，远离垃圾中文互联网。
