黑匣失联

升级群晖失败，数据挽回，处理中..

从 DSM_DS3617xs_6.2.3_25426.pat 升级 DSM_DS3617xs_6.2.3_25426_u3_patch.pat 没问题。
从 DSM_DS3617xs_6.2.3_25426_u3_patch.pat 升级 DSM_DS3617xs_6.2.4_25556.pat 失联。

• 原直通磁盘格式 ext4。
• 以下直接备份直通盘数据。

# fdisk -l
----------------------------------------------------------
Disk /dev/sdb: 465.8 GiB, 500107862016 bytes, 976773168 sectors
Disk model: HGST HTS545050A7
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0x00068095

Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 4982527 4980480 2.4G fd Linux raid autodetect
/dev/sdb2 4982528 9176831 4194304 2G fd Linux raid autodetect
/dev/sdb3 9437184 976568351 967131168 461.2G fd Linux raid autodetect

# mount /dev/sdb1 /mnt
----------------------------------------------------------
mount: /mnt: unknown filesystem type 'linux_raid_member'.

查看硬盘类型

# blkid
----------------------------------------------------------
/dev/sdb1: UUID="2405ded4-7203-b14e-3017-a5a8c86610be" TYPE="linux_raid_member" PARTUUID="00068095-01"
/dev/sdb2: UUID="7b87402d-ad61-fd7f-3017-a5a8c86610be" TYPE="linux_raid_member" PARTUUID="00068095-02"
/dev/sdb3: UUID="1fba5c5d-bb90-585d-9746-ff7e22f1caba" UUID_SUB="ff77ba4f-dc41-a070-ad73-716baef023dd" LABEL="Synology:2" TYPE="linux_raid_member" PARTUUID="00068095-03"

安装 mdadm

# apt -y install mdadm

错误

# mdadm --assemble --run /dev/md0 /dev/sdb1
----------------------------------------------------------
mdadm: no recogniseable superblock on /dev/sdb1
mdadm: /dev/sdb1 has no superblock - assembly aborted

正确

# mdadm --assemble --run /dev/md0 /dev/sdb3
----------------------------------------------------------
mdadm: /dev/md0 has been started with 1 drive.

最后

mount /dev/md0 /mnt

卸载 md0

umount /mnt
mdadm --stop /dev/md0

https://blog.jangmt.com/2016/08/linux-ubuntu-soft-raid-1-lvm.html

以上仅供提取挂载的数据然后导出，但是没有解决系统降级，解决方法：
http://www.gebi1.com/thread-287362-1-1.html

尝试中直接翻车，所幸数据已同步，轻松恢复。

后续
完整重装 DSM_DS3617xs_6.2.4_25556.pat 同样失败，直接退回上版本，至此剁下的手已接回。