====== [Draft]在已存在的 Ubuntu lvm 開機碟建立 RAID1 ======
  * 環境 : Ubuntu 20.04 採用 iso 開機預設 lvm 建立開機碟 sda(32G)
  * 目標 : 加入 sdb(32G) 設定 sda+sdb 成為 RAID1, 當 sda 損毀還能透過 sdb 開機使用, 並能加回更換後的 sda

===== 處理程序 =====
  - 確認現有 sda 內的相關資訊 <cli>
root@test-lvm-102:~# fdisk -l /dev/sda
Disk /dev/sda: 32 GiB, 34359738368 bytes, 67108864 sectors
Disk model: QEMU HARDDISK
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: gpt
Disk identifier: 4F956088-02A8-402A-931B-440831A9F332

Device       Start      End  Sectors Size Type
/dev/sda1     2048     4095     2048   1M BIOS boot
/dev/sda2     4096  4198399  4194304   2G Linux filesystem
/dev/sda3  4198400 67106815 62908416  30G Linux filesystem

root@test-lvm-102:~# df -h
Filesystem                         Size  Used Avail Use% Mounted on
udev                               941M     0  941M   0% /dev
tmpfs                              198M  1.0M  197M   1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv   30G  4.5G   24G  16% /
tmpfs                              986M     0  986M   0% /dev/shm
tmpfs                              5.0M     0  5.0M   0% /run/lock
tmpfs                              986M     0  986M   0% /sys/fs/cgroup
/dev/loop0                          62M   62M     0 100% /snap/core20/1611
/dev/sda2                          2.0G  108M  1.7G   6% /boot
/dev/loop1                          68M   68M     0 100% /snap/lxd/22753
/dev/loop2                          47M   47M     0 100% /snap/snapd/16292
tmpfs                              198M     0  198M   0% /run/user/1000

root@test-lvm-102:~# pvdisplay
  --- Physical volume ---
  PV Name               /dev/sda3
  VG Name               ubuntu-vg
  PV Size               <30.00 GiB / not usable 0
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              7679
  Free PE               0
  Allocated PE          7679
  PV UUID               1yb1vq-CMMu-7NLs-nif3-QFVU-SrAd-r81xKs

root@test-lvm-102:~# vgdisplay
  --- Volume group ---
  VG Name               ubuntu-vg
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  2
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               1
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               <30.00 GiB
  PE Size               4.00 MiB
  Total PE              7679
  Alloc PE / Size       7679 / <30.00 GiB
  Free  PE / Size       0 / 0
  VG UUID               1ZEt2r-TSxy-jyR8-TBh8-W4tf-azfb-iRn4cG

root@test-lvm-102:~# lvdisplay
  --- Logical volume ---
  LV Path                /dev/ubuntu-vg/ubuntu-lv
  LV Name                ubuntu-lv
  VG Name                ubuntu-vg
  LV UUID                7t6pa0-Fx5y-31DZ-lE1B-vKWP-v6at-nNLp0V
  LV Write Access        read/write
  LV Creation host, time ubuntu-server, 2023-12-18 21:50:55 +0000
  LV Status              available
  # open                 1
  LV Size                <30.00 GiB
  Current LE             7679
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0
</cli>
  - 安裝 mdadm 套件(Ubuntu 20.04預設已安裝)<cli>
apt install initramfs-tools mdadm
</cli>並載入 Linux Kernel<cli>
modprobe md
modprobe linear
modprobe multipath
modprobe raid0
modprobe raid1
modprobe raid5
modprobe raid6
modprobe raid10
</cli>檢查 md 狀態<cli>
root@test-lvm-102:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
unused devices: <none>
</cli>
  - 準備將 sdb 加入<cli>
root@test-lvm-102:~# sfdisk -d /dev/sda | sfdisk /dev/sdb
Checking that no-one is using this disk right now ... OK

Disk /dev/sdb: 32 GiB, 34359738368 bytes, 67108864 sectors
Disk model: QEMU HARDDISK
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

>>> Script header accepted.
>>> Script header accepted.
>>> Script header accepted.
>>> Script header accepted.
>>> Script header accepted.
>>> Script header accepted.
>>> Created a new GPT disklabel (GUID: 4F956088-02A8-402A-931B-440831A9F332).
/dev/sdb1: Created a new partition 1 of type 'BIOS boot' and of size 1 MiB.
/dev/sdb2: Created a new partition 2 of type 'Linux filesystem' and of size 2 GiB.
/dev/sdb3: Created a new partition 3 of type 'Linux filesystem' and of size 30 GiB.
/dev/sdb4: Done.

New situation:
Disklabel type: gpt
Disk identifier: 4F956088-02A8-402A-931B-440831A9F332

Device       Start      End  Sectors Size Type
/dev/sdb1     2048     4095     2048   1M BIOS boot
/dev/sdb2     4096  4198399  4194304   2G Linux filesystem
/dev/sdb3  4198400 67106815 62908416  30G Linux filesystem

The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

root@test-lvm-102:~# fdisk -l /dev/sdb
Disk /dev/sdb: 32 GiB, 34359738368 bytes, 67108864 sectors
Disk model: QEMU HARDDISK
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: gpt
Disk identifier: 4F956088-02A8-402A-931B-440831A9F332

Device       Start      End  Sectors Size Type
/dev/sdb1     2048     4095     2048   1M BIOS boot
/dev/sdb2     4096  4198399  4194304   2G Linux filesystem
/dev/sdb3  4198400 67106815 62908416  30G Linux filesystem
</cli>將 /dev/sdb2 與 /dev/sdb3 的檔案系統類型設定為 Linux RAID<cli>
root@test-lvm-102:~# fdisk /dev/sdb

Welcome to fdisk (util-linux 2.34).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help): t
Partition number (1-3, default 3): 2
Partition type (type L to list all types): 29

Changed type of partition 'Linux RAID' to 'Linux RAID'.

Command (m for help): p
Disk /dev/sdb: 32 GiB, 34359738368 bytes, 67108864 sectors
Disk model: QEMU HARDDISK
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: gpt
Disk identifier: 4F956088-02A8-402A-931B-440831A9F332

Device       Start      End  Sectors Size Type
/dev/sdb1     2048     4095     2048   1M BIOS boot
/dev/sdb2     4096  4198399  4194304   2G Linux RAID
/dev/sdb3  4198400 67106815 62908416  30G Linux filesystem

Command (m for help): t
Partition number (1-3, default 3): 3
Partition type (type L to list all types): 29

Changed type of partition 'Linux filesystem' to 'Linux RAID'.

Command (m for help): p
Disk /dev/sdb: 32 GiB, 34359738368 bytes, 67108864 sectors
Disk model: QEMU HARDDISK
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: gpt
Disk identifier: 4F956088-02A8-402A-931B-440831A9F332

Device       Start      End  Sectors Size Type
/dev/sdb1     2048     4095     2048   1M BIOS boot
/dev/sdb2     4096  4198399  4194304   2G Linux RAID
/dev/sdb3  4198400 67106815 62908416  30G Linux RAID

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
</cli>確認 /dev/sdb2 與 /dev/sdb3 內沒有 RAID 資訊<cli>
mdadm --zero-superblock /dev/sdb2
mdadm --zero-superblock /dev/sdb3
</cli>
  - 建立 RAID1 : /dev/sdb2 -> /dev/md0 , /dev/sdb3 -> /dev/md1 <cli>
mdadm --create /dev/md0 --level=1 --raid-disks=2 --metadata=0.90 missing /dev/sdb2
mdadm --create /dev/md1 --level=1 --raid-disks=2 missing /dev/sdb3

root@test-lvm-102:~# mdadm --zero-superblock /dev/sdb2
mdadm: Unrecognised md component device - /dev/sdb2
root@test-lvm-102:~# mdadm --create /dev/md0 --level=1 --raid-disks=2 missing /dev/sdb2
mdadm: Note: this array has metadata at the start and
    may not be suitable as a boot device.  If you plan to
    store '/boot' on this device please ensure that
    your boot-loader understands md/v1.x metadata, or use
    --metadata=0.90
Continue creating array?
Continue creating array? (y/n) y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
</cli>查看 md 狀態<cli>
root@test-lvm-102:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdb2[1]
      2097088 blocks [2/1] [_U]

md1 : active raid1 sdb3[1]
      31436800 blocks super 1.2 [2/1] [_U]

unused devices: <none>
</cli>格式化 /dev/md0 -> ext4 , /dev/md1 -> LVM<cli>
root@test-lvm-102:~# mkfs.ext4 /dev/md0
mke2fs 1.45.5 (07-Jan-2020)
Discarding device blocks: done
Creating filesystem with 524272 4k blocks and 131072 inodes
Filesystem UUID: f24c70d1-2144-4bd5-9870-8f2c138c940a
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912

Allocating group tables: done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

pvcreate /dev/md1
vgextend ubuntu-vg /dev/md1
pvdisplay
</cli>
  - 

===== 參考網址 =====
  * https://www.howtoforge.com/set-up-raid1-on-a-running-lvm-system-debian-etch

{{tag>lvm raid}}