我有一个 Ubuntu 19-04 LVM 安装，我想使用此处的教程将其转换为 RAID 1：
在实际系统上尝试之前，我想看看它在虚拟机上的运行情况。因此，我在 VirtualBox 上创建了一个带有 250GB 虚拟磁盘的 Ubuntu 19-04 LVM 虚拟机。然后我创建了第二个 250GB 虚拟磁盘。
运行后：
sfdisk -d /dev/sda | sfdisk --force /dev/sdb
这是 fdisk -l 的输出：
Disk /dev/sda: 250 GiB, 268435456000 bytes, 524288000 sectors
Disk model: VBOX 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: dos
Disk identifier: 0x3f9af72a
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 524285951 524283904 250G 8e Linux LVM
Disk /dev/sdb: 250 GiB, 268435456000 bytes, 524288000 sectors
Disk model: VBOX 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: dos
Disk identifier: 0x3f9af72a
两个驱动器的字节数和扇区数完全相同。
当我读到这一点时：
mdadm --create /dev/md0 --level=1 --raid-disks=2 missing /dev/sdb1
终端输出为：
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?
我注意到教程中没有提到这一点。有人能解释一下我为什么收到此消息以及它意味着什么吗？
[编辑：根据这篇文章，这没什么可担心的：https://www.howtoforge.com/how-to-set-up-software-raid1-on-a-running-lvm-system-incl-grub2-configuration-debian-squeeze-p2]
无论如何，我答应了，并继续下去。
当我读到这一点时：
pvmove -i 2 /dev/sda1 /dev/md0
终端输出为：
root@Ubuntu19:/home/mike# pvmove -i 2 /dev/sda1 /dev/md0
Insufficient free space: 63991 extents needed, but only 63967 available
Unable to allocate mirror extents for ubuntu-vg/pvmove0.
Failed to convert pvmove LV to mirrored.
这两个驱动器的大小完全相同，所以我不明白为什么没有足够的空间。
这个问题的解决方案是什么？我应该减小逻辑卷的大小吗？减小物理卷的大小？还是其他什么？
编辑：
我想尝试减小 LVM 的大小，因此我启动了 Live CD。输出如下：
root@ubuntu:/home/ubuntu# lvdisplay
WARNING: Device for PV FvC0uz-efgT-zqqB-NK3f-2yTZ-QWlO-vXuneh not found
rejected by a filter.
--- Logical volume ---
LV Path /dev/ubuntu-vg/root
LV Name root
VG Name ubuntu-vg
LV UUID RJi0Hn-fuk3-kEEe-xVeG-FqeJ-OUXR-iTpW8Y
LV Write Access read/write
LV Creation host, time ubuntu, 2019-04-15 08:25:48 +0000
LV Status NOT available
LV Size 249.01 GiB
Current LE 63747
Segments 1
Allocation inherit
Read ahead sectors auto
--- Logical volume ---
LV Path /dev/ubuntu-vg/swap_1
LV Name swap_1
VG Name ubuntu-vg
LV UUID JX3Scc-fGIM-e8Z1-zwY3-1ACM-U70M-m8OshG
LV Write Access read/write
LV Creation host, time ubuntu, 2019-04-15 08:25:48 +0000
LV Status NOT available
LV Size 976.00 MiB
Current LE 244
Segments 1
Allocation inherit
Read ahead sectors auto
当我尝试
root@ubuntu:/home/ubuntu# resize2fs /dev/ubuntu-vg/root 248GB
我有：
resize2fs 1.44.6 (5-Mar-2019)
open: No such file or directory while opening /dev/ubuntu-vg/root
答案1
好的，我明白了。
我跑完之后：
sfdisk -d /dev/sda | sfdisk --force /dev/sdb
在使用 fdisk 更改分区类型之前，我启动了实时 CD 并执行了以下操作：
ubuntu@ubuntu:~$ sudo su
root@ubuntu:/home/ubuntu# lvdisplay
--- Logical volume ---
LV Path /dev/ubuntu-vg/root
LV Name root
VG Name ubuntu-vg
LV UUID RJi0Hn-fuk3-kEEe-xVeG-FqeJ-OUXR-iTpW8Y
LV Write Access read/write
LV Creation host, time ubuntu, 2019-04-15 08:25:48 +0000
LV Status available
# open 0
LV Size 249.01 GiB
Current LE 63747
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
--- Logical volume ---
LV Path /dev/ubuntu-vg/swap_1
LV Name swap_1
VG Name ubuntu-vg
LV UUID JX3Scc-fGIM-e8Z1-zwY3-1ACM-U70M-m8OshG
LV Write Access read/write
LV Creation host, time ubuntu, 2019-04-15 08:25:48 +0000
LV Status available
# open 0
LV Size 976.00 MiB
Current LE 244
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
root@ubuntu:/home/ubuntu# e2fsck -f /dev/ubuntu-vg/root
e2fsck 1.44.6 (5-Mar-2019)
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/ubuntu-vg/root: 201304/16326656 files (0.1% non-contiguous),
2764077/65276928 blocks
root@ubuntu:/home/ubuntu# resize2fs /dev/ubuntu-vg/root 247G
resize2fs 1.44.6 (5-Mar-2019)
Resizing the filesystem on /dev/ubuntu-vg/root to 65011712 (4k)
blocks.
The filesystem on /dev/ubuntu-vg/root is now 65011712 (4k) blocks
long.
root@ubuntu:/home/ubuntu# lvreduce -L 248G /dev/ubuntu-vg/root
WARNING: Reducing active logical volume to <248.82 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce ubuntu-vg/root? [y/n]: y
Size of logical volume ubuntu-vg/root changed from 249.01 GiB (63747
extents) to <248.82 GiB (63697 extents).
Logical volume ubuntu-vg/root successfully resized.
root@ubuntu:/home/ubuntu#
重新启动我的虚拟机，之后一切就顺利了。