原QNAP NAS Raid1磁盘超级块被擦除后的数据恢复求助

问题背景 #

我有一块原本在QNAP NAS里的磁盘（之前和另一块盘组成Raid1，那块盘我还留着）。NAS坏了之后，我在Ubuntu机器上用mdadm创建了RAID阵列，成功挂载并读取了数据。

但关机再开机后，就没法挂载任何东西了——mdadm报错说设备忙。我试了一堆办法（包括重启）都没能重新挂载。情急之下我犯了个大错，对这块盘的所有分区都执行了mdadm --zero-superblock，现在彻底搞砸了，除了骂自己啥也干不了。

当前设备状态 #

lsblk输出 #

sdc        8:32   0   2,7T  0 disk
├─sdc1     8:33   0 517,7M  0 part
│ └─md11   9:11   0 516,7M  0 raid1
├─sdc2     8:34   0 517,7M  0 part
│ └─md12   9:12   0 516,7M  0 raid1
├─sdc3     8:35   0   2,7T  0 part
├─sdc4     8:36   0 517,7M  0 part  /media/myuser/2ed9e1b2-2659-4202-9066-bd3246353f1d
└─sdc5     8:37   0     8G  0 part
  └─md15   9:15   0     8G  0 raid1
md13       9:13   0     0B  0 md

这块盘确实有5个分区，我核心需要访问的是/dev/sdc3。奇怪的是Ubuntu不用任何操作就能自动挂载/dev/sdc4。

LVM检测结果（lvm fullreport输出） #

lvm fullreport
WARNING: wrong checksum 0 in mda header on /dev/sdc3 at 4096
WARNING: wrong magic number in mda header on /dev/sdc3 at 4096
WARNING: wrong version 0 in mda header on /dev/sdc3 at 4096
WARNING: wrong start sector 0 in mda header on /dev/sdc3 at 4096
WARNING: bad metadata header on /dev/sdc3 at 4096.
WARNING: scanning /dev/sdc3 mda1 failed to read metadata summary.
WARNING: repair VG metadata on /dev/sdc3 with vgck --updatemetadata.
WARNING: scan failed to get metadata summary from /dev/sdc3 PVID A0oBICVnS2UPgax0Y8H2F5lgP2L3Xa3D
Fmt  PV UUID                                DevSize PV         Maj Min PMdaFree  PMdaSize  PExtVsn 1st PE  PSize  PFree  Used Attr Allocatable Exported   Missing    PE  Alloc PV Tags #PMda #PMdaUse BA Start BA Size PInUse Duplicate
lvm2 A0oBIC-VnS2-UPga-x0Y8-H2F5-lgP2-L3Xa3D  <2,72t /dev/sdc3  8   35         0         0        1   1,00m <2,72t <2,72t   0  ---                                      0     0             0        0       0       0

Start SSize PV UUID                                LV UUID
0     0 A0oBIC-VnS2-UPga-x0Y8-H2F5-lgP2-L3Xa3D

我/etc/lvm目录里有一些备份文件，但已经搞砸太多了，不敢再随便操作，怕雪上加霜。

已尝试的操作 #

我在各大论坛搜了很多办法，最主要的是尝试重新创建RAID阵列：

mdadm --create --assume-clean /dev/md0 --level=1 --raid-devices=2 /dev/sdc3 missing

但之后尝试挂载/dev/md0时，得到报错：

mount: /mnt/1: wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error.

而且此时执行lvm fullreport没有任何输出。

补充信息1（blkid输出） #

/dev/sdc: PTUUID="170dad0b-6e63-4bbc-835e-9c7e901e3d4d" PTTYPE="gpt"
/dev/sdc2: UUID="2d0918c5-2ae2-6736-cb3a-9dfb2f014dc0" UUID_SUB="7b071e98-21b9-2459-7b3d-232247796426" LABEL="home-x1-carbon:12" TYPE="linux_raid_member" PARTLABEL="primary" PARTUUID="61b68a0d-0ebc-4379-9d8e-9694a0edc09d"
/dev/sdc5: UUID="2d279112-312e-1a89-d597-da4cc01c2a92" UUID_SUB="72243364-539b-6614-53c2-374e28a6a4e7" LABEL="home-x1-carbon:15" TYPE="linux_raid_member" PARTLABEL="primary" PARTUUID="29af1fc5-57ab-4da4-ac38-d3d9955072b5"
/dev/sdc3: UUID="01f77d36-7ed1-f4be-6948-820e41b0956a" UUID_SUB="c78c6ff9-63bb-002f-93a4-c901bdb14307" LABEL="home-x1-carbon:0" TYPE="linux_raid_member" PARTLABEL="primary" PARTUUID="4feebb7b-0a90-490c-a516-3fdca113592f"
/dev/sdc1: UUID="4a443aca-7fbe-197c-0bcb-72ec6c0c3ce0" UUID_SUB="55bf9203-a7ca-a8a3-4cdb-5cef7f12e54f" LABEL="home-x1-carbon:11" TYPE="linux_raid_member" PARTLABEL="primary" PARTUUID="22efde15-2e64-4cf5-b220-21ee5c57aed2"
/dev/sdc4: UUID="2ed9e1b2-2659-4202-9066-bd3246353f1d" BLOCK_SIZE="4096" TYPE="ext3" PARTLABEL="primary" PARTUUID="d5ae2202-0f7b-4c30-b7c3-f9d84de4b14e"

执行blkid /dev/md0没有任何输出。

补充信息2（执行创建RAID后的状态） #

再次执行创建RAID命令后：

# mdadm --create --assume-clean /dev/md0 --level=1 --raid-devices=2 /dev/sdc3 missing
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? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

此时lsblk显示/dev/md0已和/dev/sdc3关联：

sdc        8:32   0   2,7T  0 disk
├─sdc1     8:33   0 517,7M  0 part
│ └─md11   9:11   0 516,7M  0 raid1
├─sdc2     8:34   0 517,7M  0 part
│ └─md12   9:12   0 516,7M  0 raid1
├─sdc3     8:35   0   2,7T  0 part
│ └─md0    9:0    0   2,7T  0 raid1
├─sdc4     8:36   0 517,7M  0 part  /media/dani/2ed9e1b2-2659-4202-9066-bd3246353f1d
└─sdc5     8:37   0     8G  0 part
  └─md15   9:15   0     8G  0 raid1
md13       9:13   0     0B  0 md

但挂载仍然失败，报错和之前完全一致：

# mount /dev/md0 /mnt/1
mount: /mnt/1: wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error.

我还有另一块RAID1的磁盘，理论上数据是一致的，但在搞砸那块之前，我想先看看能不能把这块盘救回来。恳请各位大佬给点帮助！

备注：内容来源于stack exchange，提问作者Daniele