远程 Debian 服务器的分区扩大了，现在无法启动

Question

我有一台 Debian 10 服务器（托管在 IONOS 上）。我将 SSD 的大小从 240 GB 增加到了 400 GB。

然后我想增加分区的大小以使用该空间。我曾经fdisk删除并重新创建/dev/sda2。重新启动后，服务器停止响应。

IONOS 开发人员说数据丢失了。他说得对吗？为什么？发生了什么？

以下是扩大磁盘之前的命令和输出：

# fdisk -l

Disk /dev/sda: 240 GiB, 257698037760 bytes, 503316480 sectors
Disk model: Virtual disk
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: 0xbc873d4a

Device     Boot  Start       End   Sectors   Size Id Type
/dev/sda1  *      2048    999423    997376   487M 83 Linux
/dev/sda2       999424 503316479 502317056 239.5G 8e Linux LVM

Disk /dev/mapper/vg00-lv01: 237.6 GiB, 255135318016 bytes, 498311168 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/vg00-lv00: 1.9 GiB, 2046820352 bytes, 3997696 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/loop0: 63.5 MiB, 66527232 bytes, 129936 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/loop1: 118.2 MiB, 123973632 bytes, 242136 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/loop3: 118.2 MiB, 123973632 bytes, 242136 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/loop4: 44.3 MiB, 46419968 bytes, 90664 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/loop5: 44.5 MiB, 46682112 bytes, 91176 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/loop6: 63.5 MiB, 66531328 bytes, 129944 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

增加磁盘大小后：

# fdisk -l

Disk /dev/sda: 400 GiB, 429496729600 bytes, 838860800 sectors
Disk model: Virtual disk
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: 0xbc873d4a

Device     Boot  Start       End   Sectors   Size Id Type
/dev/sda1  *      2048    999423    997376   487M 83 Linux
/dev/sda2       999424 503316479 502317056 239.5G 8e Linux LVM

Disk /dev/mapper/vg00-lv01: 237.6 GiB, 255135318016 bytes, 498311168 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/vg00-lv00: 1.9 GiB, 2046820352 bytes, 3997696 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/loop0: 63.5 MiB, 66531328 bytes, 129944 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/loop1: 118.2 MiB, 123973632 bytes, 242136 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/loop2: 63.5 MiB, 66527232 bytes, 129936 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/loop3: 44.5 MiB, 46682112 bytes, 91176 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/loop4: 44.3 MiB, 46419968 bytes, 90664 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/loop5: 118.2 MiB, 123973632 bytes, 242136 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

这是我做的：

# fdisk /dev/sda

Welcome to fdisk (util-linux 2.33.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help): p
Disk /dev/sda: 400 GiB, 429496729600 bytes, 838860800 sectors
Disk model: Virtual disk
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: 0xbc873d4a

Device     Boot  Start       End   Sectors   Size Id Type
/dev/sda1  *      2048    999423    997376   487M 83 Linux
/dev/sda2       999424 503316479 502317056 239.5G 8e Linux LVM

Command (m for help): d
Partition number (1,2, default 2): 2

Partition 2 has been deleted.

Command (m for help): n
Partition type
   p   primary (1 primary, 0 extended, 3 free)
   e   extended (container for logical partitions)
Select (default p): e
Partition number (2-4, default 2): 2
First sector (999424-838860799, default 999424):
Last sector, +/-sectors or +/-size{K,M,G,T,P} (999424-838860799, default 838860799):

Created a new partition 2 of type 'Extended' and of size 399.5 GiB.
Partition #2 contains a LVM2_member signature.

Do you want to remove the signature? [Y]es/[N]o: N

Command (m for help): p

Disk /dev/sda: 400 GiB, 429496729600 bytes, 838860800 sectors
Disk model: Virtual disk
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: 0xbc873d4a

Device     Boot  Start       End   Sectors   Size Id Type
/dev/sda1  *      2048    999423    997376   487M 83 Linux
/dev/sda2       999424 838860799 837861376 399.5G  5 Extended

Command (m for help): w
The partition table has been altered.
Syncing disks.

# reboot

在 IONOS UI 中的 KVM 控制台中，我看到了以下错误：

Volume Group "vg00" not found（重复多次）

ALERT! /dev/mapper/vg00-lv01 does not exist.

Answer 1

当前/dev/sda2分区是扩展分区，是用于存放逻辑分区的容器。现在没有哪个正常的工具会期望文件系统或 LVM 结构直接位于其中。

你应该不是现在尝试创建任何逻辑分区。

如果可以使用fdisk，请删除sda2（就像您所做的那样）并将其重新创建为主分区。指定999424为起始扇区（就像您所做的那样）。新分区可能与当前分区一样大sda2，但它必须至少与旧分区一样大sda2。重点是它应该是基本的，未扩展；p询问时按。将分区重新创建为主分区后，使用命令t为新分区指定sda2类型8e（Linux LVM），即旧分区sda2曾经具有的类型。

如果你不能使用fdisk类似的工具，也许你可以启动一个实时发行版（比如 Knoppix DVD）并使用它是 fdisk修复有问题的分区表。请记住，磁盘可能是sda或sdb，或者实时发行版中的其他内容。

如果您甚至无法做到这一点，并且您所拥有的只是一个非常有限的 initramfs 环境，那么仍然可能有办法。POSIX shell、POSIXprintf和 POSIXdd足以“极其手动地”将分区类型更改为8e。在继续之前，请注意本答案后面的命令假设或基于以下内容：

• 该磁盘是/dev/sda。
• 分区表的类型是dos（在您的情况下是）。
• 您想写十六进制8e，即八进制216。
• 您希望写入存储分区类型的正确偏移量。对于dos分区表，相应的偏移量为：
  • 分区 1 的十进制数为 446+4=450，
  • 分区 2 的十进制数为 462+4=466（这是您的情况），
  • 分区 3 的十进制值为 478+4=482，
  • 分区 4 的十进制数为 494+4=498。

以下命令应该可以按原样工作，但其他想要执行类似操作的用户可能需要调整一些值。命令为：

printf '\216' | dd of=/dev/sda bs=1 seek=466 count=1 conv=notrunc

（conv=notrunc在向块设备写入数据时实际上不需要/dev/sda，但它不会造成任何危害。我使用它以防有人想使用该命令来修改存储在常规文件中的图像；在这种情况下conv=notrunc是必须的。）

修复分区类型后，重新启动。操作系统应该可以正常启动。下一步是扩展 LVM 结构；本答案未涵盖此内容。