【背景】
前几日因为电源插头松动等原因导致频繁掉电；
同时，由于又使用了傲腾做缓存。
在某一日重启之后，虚拟机就没法启动了。
应该是硬盘出了问题。但是因为电源问题， 没法整。
这两天新买的电源回来了，插上硬盘开始尝试修复
【环境】
win10 ltsc
vmware
dsm6.2
1T+1T 储存池 raid0 NTFS==》 虚拟1T vmdk
4T basic NTFS ==》虚拟4T vmdk
【过程】
因为只是1T的挂掉了，所以只用修复1t的
1.因为是raid0，可以取出一个硬盘，以防万一
2.新建一个ubuntu的虚拟机，安装相关软件
sudo -i # 所以步骤都需要管理员权限
apt update && apt install -y mdadm lvm2 btrfs-prog
3.备份一个副本
参考1
参考2
dd if=/dev/sdd of=1t.img bs=8M # 使用dd备份镜像，尽量不动原始数据
losetup --partscan --find --show 1t.img # 扫描 loop 设备
lsblk # 扫描一下，如果没有出现loop再尝试下面的，我好像没有用到下面的
#mkdir $DISK_PATH0 # 挂载 loop，可能不大需要
#mount /dev/loop0pX $DISK_PATH0
3.群晖默认启用软raid，所以要挂载软raid
参考3
mdadm -Av /dev/md3 /dev/loop18p3 #挂载loop
lsblk # 检查一下，出现下面这种就是正常的——————————————loop18 7:18 0 1000G 0 loop
├─loop18p1 259:3 0 2.4G 0 loop
├─loop18p2 259:4 0 2G 0 loop
└─loop18p3 259:5 0 995.4G 0 loop └─md3 9:3 0 995.4G 0 raid1
4.磁盘修复
参考4
按照官当的文档，下一步直接挂载md3就可以读出数据了。
不过可能是我的损坏的比较厉害，挂载报错，只能再想办法了。
一定要确定文件系统，我之前以为是ext4，结果证明是btrfs，还好是在镜像上操作的。
如果不确定可以试试fsck.ext4会有提示
btrfs-find-root /dev/md3 &> /tmp/root.txt
head /tmp/root.txt
______
Couldn't setup extent tree
Superblock thinks the generation is 12684
Superblock thinks the level is 1
Found tree root at 394632675328 gen 12684 level 1
Well block 394631839744(gen: 12683 level: 1) seems good, but generation/level doesn't match, want gen: 12684 level: 1
Well block 394631561216(gen: 12682 level: 1) seems good, but generation/level doesn't match, want gen: 12684 level: 1
Well block 394631364608(gen: 12681 level: 1) seems good, but generation/level doesn't match, want gen: 12684 level: 1
Well block 394630971392(gen: 12680 level: 1) seems good, but generation/level doesn't match, want gen: 12684 level: 1
Well block 394630627328(gen: 12679 level: 1) seems good, but generation/level doesn't match, want gen: 12684 level: 1
Well block 394630348800(gen: 12678 level: 1) seems good, but generation/level doesn't match, want gen: 12684 level: 1
______
btrfs check --tree-root <block> --super <sup>
# <block> 从上往下尝试 ，如394631839744，<sup> = 0/1/2# 跟参考4中的不一样，我这里报错了，多了个Error
————————
Invalid key type(BLOCK_GROUP_ITEM) found in root(202)
ignoring invalid key
Invalid key type(BLOCK_GROUP_ITEM) found in root(202)
ignoring invalid key
Invalid key type(BLOCK_GROUP_ITEM) found in root(202)
ignoring invalid key
Invalid key type(BLOCK_GROUP_ITEM) found in root(202)
ignoring invalid key
checking free space cache
cache and super generation don't match, space cache will be invalidated
checking fs roots
checking csums
checking root refs
ERROR: transid errors in file system
found 296381579264 bytes used, error(s) found
total csum bytes: 290972
total tree bytes: 298598400
total fs tree bytes: 280166400
total extent tree bytes: 17727488
btree space waste bytes: 54920864
file data blocks allocated: 359966142464referenced 359930527744
————————
btrfs check --repair --tree-root <block> --super <sup> #我使用了跟上面一样的参数，这次就没什么问题
#但是如果再次使用上面的命令，还是一样的报错
————————
Invalid key type(BLOCK_GROUP_ITEM) found in root(202)
ignoring invalid key
Invalid key type(BLOCK_GROUP_ITEM) found in root(202)
ignoring invalid key
Invalid key type(BLOCK_GROUP_ITEM) found in root(202)
ignoring invalid key
No device size related problem found
checking free space cache
cache and super generation don't match, space cache will be invalidated
checking fs roots
checking csums
checking root refs
found 296381579264 bytes used, no error found
total csum bytes: 290972
total tree bytes: 298598400
total fs tree bytes: 280166400
total extent tree bytes: 17727488
btree space waste bytes: 54920864
file data blocks allocated: 359966142464referenced 359930527744
————————
btrfs rescue super-recover /dev/md3
# All supers are valid, no need to recover
# 既然这一步啥也没干，那就尝试挂载吧mkdir btrfs
root@m-server:/media/ubuntu# mount /dev/md3 ./btrfs/
root@m-server:/media/ubuntu# ls btrfs/
bo_nas @download oct_nas svn @synophoto-bin-r.core @synophoto-geoco.core @synorcd.core
@database @eaDir @pulseaudio.core @synoaudiod.core @synophoto-bin-t.core @synophoto-perso.core TimeMachine
DDSM1 homes R1 @synoelasticd.core @synophoto-conce.core @synophoto-task-.core @tmp
ddsm2 @ipcalc.core @sharesnap @synologydrive @synophoto-face-.core @synophoto-thumb.core# 挂载成功，愉快的拷贝出来就可以了