Synology blue led of death (led blinking)

I found the solution this way.

I removed ALL the disks an formated one of the disk (you'd better use a new one. I had a backup so didn't take much risk doing this) using

• parted
• mklabel gpt
• write
• quit

I inserted this only disk in the last slot of my synology server. and rebooted it. At this moment synology assistant was able to install a new dsm version.

After installation of the dsm , I choose not to configure a raid.([https://www.synology.com/en-us/knowledgebase/DSM/tutorial/General/How_to_reset_your_Synology_NAS]) reboot the synology.

Once rebooted, I added the 9 old other disks and connected with ssh to my synology.

Find out raid information on your disks

bash-4.3# mdadm --examine /dev/sd[a-z] 
mdadm: No md superblock detected on /dev/sda.
mdadm: No md superblock detected on /dev/sdb.
mdadm: No md superblock detected on /dev/sdc.
mdadm: No md superblock detected on /dev/sdd.
mdadm: No md superblock detected on /dev/sde.
mdadm: No md superblock detected on /dev/sdf.
mdadm: No md superblock detected on /dev/sdg.
mdadm: No md superblock detected on /dev/sdh.
mdadm: No md superblock detected on /dev/sdi.
mdadm: No md superblock detected on /dev/sdj

Those are the raid configured by the DSM so, didn't find anything on my disks

bash-4.3# cat /proc/mdstat 
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] 
md1 : active raid1 sdj2[0]
      2097088 blocks [10/1] [U_________]

md0 : active raid1 sdj1[0]
      2490176 blocks [10/1] [U_________]

Trying to assemble raids with scan option

bash-4.3# mdadm --assemble --scan

Seems to work !

bash-4.3# cat /proc/mdstat 
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] 
md125 : active raid1 sda1[0] sdi1[8] sdh1[7] sdg1[6] sdf1[5] sde1[4] sdd1[3] sdc1[2] sdb1[1]
      2490176 blocks [10/9] [UUUUUUUUU_]

md126 : active raid1 sda2[0] sdi2[8] sdh2[7] sdg2[6] sdf2[5] sde2[4] sdd2[3] sdc2[2] sdb2[1]
      2097088 blocks [10/9] [UUUUUUUUU_]

md127 : active raid5 sda5[0] sdi5[8] sdh5[7] sdg5[6] sdf5[5] sde5[4] sdd5[3] sdc5[2] sdb5[1]
      35120552832 blocks super 1.2 level 5, 64k chunk, algorithm 2 [10/9] [UUUUUUUUU_]

md1 : active raid1 sdj2[0]
      2097088 blocks [10/1] [U_________]

md0 : active raid1 sdj1[0]
      2490176 blocks [10/1] [U_________]

unused devices: <none>

Now, I'd like to be able to mount my raids.

I'll try to mount the raid md127 as it seems to be the biggest one (the one containing my data)

bash-4.3# mkdir /volume_restore
bash-4.3# mount /dev/md127 /volume_restore/
mount: unknown filesystem type 'LVM2_member'

I try to find some information about the Volume Group

bash-4.3# vgdisplay 
  --- Volume group ---
  VG Name               vg1000
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  2
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               32.71 TiB
  PE Size               4.00 MiB
  Total PE              8574353
  Alloc PE / Size       8574353 / 32.71 TiB
  Free  PE / Size       0 / 0   
  VG UUID               Mxjnuy-PmQl-3TBT-zUa2-kBj8-j3AO-PNibo3

There is a Volume Group

bash-4.3# lvdisplay 
  --- Logical volume ---
  LV Path                /dev/vg1000/lv
  LV Name                lv
  VG Name                vg1000
  LV UUID                u1Ik6T-BQDC-ljKt-TocR-brIQ-5g6R-BR0JTv
  LV Write Access        read/write
  LV Creation host, time , 
  LV Status              NOT available
  LV Size                32.71 TiB
  Current LE             8574353
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto

And a logical Volume

A can't find the vg1000 in /dev/vg1000. I seems to be inactive. So I activate it doing:

bash-4.3# vgchange -ay
  1 logical volume(s) in volume group "vg1000" now active

Now I'm able to mount it!

mount /dev/vg1000/lv /volume_restore/

@ this point make a backup !

We'll now "merge the raids"

bash-4.3# cat /proc/mdstat 
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] 
md125 : active raid1 sda1[0] sdi1[8] sdh1[7] sdg1[6] sdf1[5] sde1[4] sdd1[3] sdc1[2] sdb1[1]
      2490176 blocks [10/9] [UUUUUUUUU_]

md126 : active raid1 sda2[0] sdi2[8] sdh2[7] sdg2[6] sdf2[5] sde2[4] sdd2[3] sdc2[2] sdb2[1]
      2097088 blocks [10/9] [UUUUUUUUU_]

md127 : active raid5 sda5[0] sdi5[8] sdh5[7] sdg5[6] sdf5[5] sde5[4] sdd5[3] sdc5[2] sdb5[1]
      35120552832 blocks super 1.2 level 5, 64k chunk, algorithm 2 [10/9] [UUUUUUUUU_]

md1 : active raid1 sdj2[0]
      2097088 blocks [10/1] [U_________]

md0 : active raid1 sdj1[0]
      2490176 blocks [10/1] [U_________]

md125 seems to be the old root partition of my former RAID . I'll try to propagate the md0 to all the disks

first stop /dev/md125

mdadm --stop /dev/md125

check that'is stopped

bash-4.3# cat /proc/mdstat 
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] 
md126 : active raid1 sda2[0] sdi2[8] sdh2[7] sdg2[6] sdf2[5] sde2[4] sdd2[3] sdc2[2] sdb2[1]
      2097088 blocks [10/9] [UUUUUUUUU_]

md127 : active raid5 sda5[0] sdi5[8] sdh5[7] sdg5[6] sdf5[5] sde5[4] sdd5[3] sdc5[2] sdb5[1]
      35120552832 blocks super 1.2 level 5, 64k chunk, algorithm 2 [10/9] [UUUUUUUUU_]

md1 : active raid1 sdj2[0]
      2097088 blocks [10/1] [U_________]

md0 : active raid1 sdj1[0]
      2490176 blocks [10/1] [U_________]

now add all the former partitions of your disks to the raid

bash-4.3# /sbin/mdadm --add /dev/md0 /dev/sda1 /dev/sdi1 /dev/sdh1 /dev/sdg1 /dev/sdf1 /dev/sdc1 /dev/sdb1
mdadm: added /dev/sda1
mdadm: added /dev/sdi1
mdadm: added /dev/sdh1
mdadm: added /dev/sdg1
mdadm: added /dev/sdf1
mdadm: added /dev/sdc1
mdadm: added /dev/sdb1

check if it worked

bash-4.3# cat /proc/mdstat 
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] 
md126 : active raid1 sda2[0] sdi2[8] sdh2[7] sdg2[6] sdf2[5] sde2[4] sdd2[3] sdc2[2] sdb2[1]
      2097088 blocks [10/9] [UUUUUUUUU_]

md127 : active raid5 sda5[0] sdi5[8] sdh5[7] sdg5[6] sdf5[5] sde5[4] sdd5[3] sdc5[2] sdb5[1]
      35120552832 blocks super 1.2 level 5, 64k chunk, algorithm 2 [10/9] [UUUUUUUUU_]

md1 : active raid1 sdj2[0]
      2097088 blocks [10/1] [U_________]

md0 : active raid1 sdb1[10](S) sdc1[11](S) sdf1[12](S) sdg1[13](S) sdh1[14](S) sdi1[15](S) sda1[16] sdj1[0]
      2490176 blocks [10/1] [U_________]
      [>....................]  recovery =  2.4% (60032/2490176) finish=3.3min speed=12006K/sec

You can do the same for md1

For you're data raid, you'll need to create the partition (in my case sdj5) on your "new disk".

I did it quite easily using parted on /dev/sda to know the propreties of the partition

rbash-4.3# parted /dev/sda
GNU Parted 3.2
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print                                                            
print
Model: WDC WD4000F9YZ-09N20 (scsi)
Disk /dev/sda: 4001GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system     Name  Flags
 1      131kB   2550MB  2550MB  ext4                  raid
 2      2550MB  4698MB  2147MB  linux-swap(v1)        raid
 5      4840MB  4001GB  3996GB                        raid

The created the same partition using parted /dev/sdj

bash-4.3# parted /dev/sdj
mkpart primary 4840MB 4001GB
set 1 raid on
Model: WDC WD4000F9YZ-09N20 (scsi)
Disk /dev/sdj: 4001GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system     Name  Flags
 1      1049kB  2551MB  2550MB  ext4                  raid
 2      2551MB  4699MB  2147MB  linux-swap(v1)        raid
 3      4840MB  4001GB  3996GB                        raid
quit

At this time it created a partition n°3 but I don't mind.

I only need to add this partition to my raid doing:

bash-4.3# /sbin/mdadm --add /dev/md127 /dev/sdj3

You can then check if your raid is rebuilding with

bash-4.3# cat /proc/mdstat