How to Replace a Faulted OS Drive with MD RAID in Hyperion

Written By Sebastian Sime (Administrator)

Updated at June 19th, 2026

Table of Contents

Identify the new drive Create partitions Reload Partitions Recreate MD RAID Add Missing Devices to MD RAID Restore EFI Boot Loader Mirroring Add New Boot Option for the New Drive Ensure Correct Boot Order Copy the EFI Files to the New EFI Partition Health Checks

→ Applies to: Hyperion 9.x and above

IMPORTANT
Before physically replacing a drive, attempt to recover the degraded array using the transient error recovery procedure described in ("Troubleshooting MD RAID Degraded Alert in Hyperion")
OS drives are not visible in the SynetoOS UI. In case of failure, the original RAID configuration must be reconfigured from the CLI.

Step 1. Connect to Hyperion appliance via SSH as admin

ssh admin@<your_ip_address_or_hostname>

Step 2. Become Super User

sudo su

Identify the new drive

Find the new Drive

lsblk -o NAME,SIZE,MOUNTPOINT,TYPE,VENDOR,MODEL,SERIAL

EXAMPLE OUTPUT

NAME          SIZE MOUNTPOINT  TYPE  VENDOR   MODEL            SERIAL
nvme9n1     931.5G             disk  Samsung  SSD 980 PRO 1TB  S5GXNX0R123456W
├─nvme9n1p1   600M /boot/efi   part                            S5GXNX0R123456W-1
├─nvme9n1p2     2G /boot       part                            S5GXNX0R123456W-2
└─nvme9n1p3   200G             part                            S5GXNX0R123456W-3
  └─md127     200G /           raid1                           
nvme6n1     931.5G             disk  Samsung  SSD 980 PRO 1TB  S6B0NX0Z987654A

The new drive has no partitions. Note its device path (used as /dev/nvme6n1 in this guide) and the existing healthy drive (used as /dev/nvme9n1).

Create partitions

The MD RAID configuration is created on top of drive partitions instead of full drives, so in order to recreate it, we will need to partition the newly added drives with partitions having the exact same sizes as the other half of the RAID configuration. Partition order is not relevant, but for consistency we recommend respecting the order as explained below.

IMPORTANT
SynetoOS below 6.1: On older versions, /boot/efi existed only on Drive 1.

Drive 1 fails → reinstall required
Drive 2 fails → rebuild without reinstall

Step 1. Start parted

parted /dev/nvme6n1

Step 2. Create a new, empty, GPT partition table

mklabel gpt

Step 3. Create Partition 1

If you're on SynetoOS 6.1 and above – EFI System (600 MB):

mkpart "EFI" fat32 1MiB 601MiB

If you're on SynetoOS below 6.1 – Linux Boot (2 GB):

mkpart primary "boot" 1MiB 2049MiB

Step 4. Flag Partition 1

If you're on SynetoOS 6.1 and above – flag as EFI System Partition (ESP):

set 1 esp on

If you're on SynetoOS below 6.1 – flag for Linux Software RAID (mdraid):

set 1 raid on

Step 5. Create Partition 2

If you're on SynetoOS 6.1 and above – Linux Boot (2 GB):

mkpart "boot" xfs 601MiB 2649MiB

If you're on SynetoOS below 6.1 – Linux Root (200 GB):

mkpart primary "os" 2049MiB 202049MiB

Step 6. Flag Partition 2 for Linux Software RAID (mdraid)

If you're on SynetoOS 6.1 and above:

set 2 raid on

If you're on SynetoOS below 6.1:

set 2 raid on

Step 7. Create Partition 3 – Linux Root (200 GB)

mkpart "os" xfs 2649MiB 202649MiB

Step 8. Flag the partition for RAID

If you're on SynetoOS 6.1 and above:

mkpart "os" xfs 2649MiB 202649MiB

If you're on SynetoOS below 6.1 does not have a third partition

Step 9. Exit parted

quit

Reload Partitions

After creating partitions, reload the partition table in the Linux kernel to avoid a reboot.

Step 1. Reload partitions

partprobe /dev/nvme6n1

Step 2. Verify layout

lsblk -o NAME,SIZE,TYPE /dev/nvme6n1

EXAMPLE OUTPUT

NAME           SIZE TYPE
nvme6n1      894.3G disk
├─nvme6n1p1    600M part
├─nvme6n1p2      2G part
└─nvme6n1p3  195.3G part

Recreate MD RAID

Step 1. Check RAID health

For a quick summary:

cat /proc/mdstat

For a comprehensive technical report:

mdadm --detail /dev/md126

mdadm --detail /dev/md127

Step 2. Check the block devices (disks and partitions)

lsblk -o NAME,SIZE,TYPE,MOUNTPOINTS,VENDOR,MODEL,SERIAL,UUID

EXAMPLE OUTPUT

NAME          SIZE TYPE  MOUNTPOINTS   VENDOR   MODEL             SERIAL
nvme9n1     931.5G disk                Samsung  SSD 980 PRO 1TB   S5GXNX0R123456W
├─nvme9n1p1   600M part  /boot/efi                                
├─nvme9n1p2     2G part                                           
│ └─md126       2G raid1 /boot                                    
└─nvme9n1p3   200G part                                           
  └─md127     200G raid1 /                                        
nvme6n1     931.5G disk                Samsung  SSD 980 PRO 1TB   S6B0NX0Z987654A
├─nvme6n1p1   600M part                                           
├─nvme6n1p2     2G part                                           
└─nvme6n1p3   200G part

Use to identify:

Partition size	RAID device	Mount point
~2 GB	`md126`	`/boot`
~200 GB	`md127`	`/` (root)

Step 3. Check all block devices attributes

blkid | grep -v md

EXAMPLE OUTPUT

/dev/nvme9n1p1: UUID="8CFD-CE0A" TYPE="vfat" PARTLABEL="EFI" PARTUUID="90486c99-677c-429e-830b-37474934819b"
/dev/nvme9n1p2: UUID="85351337-b9b6-4c31-90ae-9d9ba4129a6a" TYPE="xfs" PARTLABEL="boot" PARTUUID="4a8807dd-c9ef-49a6-8bb0-49040b70ddb3"
/dev/nvme9n1p3: UUID="7263bc5d-d413-4ab5-b1dc-a7dca81b74ca" TYPE="xfs" PARTLABEL="os" PARTUUID="f033cf84-3a89-42e3-bd04-c823d15618f2"
/dev/nvme6n1p1: UUID="8BDD-B465" TYPE="vfat" PARTLABEL="EFI" PARTUUID="e771da92-9132-4f34-bc20-258632af4603"
/dev/nvme6n1p2: UUID="dda80697-1a96-4ace-8111-d495e155e0b7" TYPE="xfs" PARTLABEL="boot" PARTUUID="dda80697-1a96-4ace-8111-d495e155e0b7"
/dev/nvme6n1p3: UUID="38b08ed6-2179-402a-aa81-1c58e7a1f7a5" TYPE="xfs" PARTLABEL="os" PARTUUID="38b08ed6-2179-402a-aa81-1c58e7a1f7a5"
/dev/zram0: LABEL="zram0" UUID="d8a46f61-cdf5-4910-aa82-9609a1c3fabd" TYPE="swap"

Step 4. Confirm drive used in MD RAID

mdadm --examine /dev/nvme6n1p1

mdadm --examine /dev/nvme6n1p2

Add Missing Devices to MD RAID

Step 1. Add to /boot RAID

mdadm --add /dev/md126 /dev/nvme6n1p2

Step 2. Add to /root RAID

mdadm --add /dev/md127 /dev/nvme6n1p3

Step 3. Check boot RAID progress

cat /proc/mdstat

EXAMPLE OUTPUT
md126 : active raid1 nvme9n1p2[1] nvme6n1p2[2]
   [==>..................] recovery = 12.3% ...
Wait until the rebuild process completes before proceeding.

Step 4. Verify MD RAID status

mdadm --detail /dev/md126

mdadm --detail /dev/md127

Ensure the following 2 lines are as follow:
State : clean
Active Devices : 2

Restore EFI Boot Loader Mirroring

Applies only on SynetoOS 6.1 version and above

Step 1. List the boot option names from the system's EFI

efibootmgr -v

EXAMPLE OUTPUT

BootCurrent: 0000
Timeout: 1 seconds
BootOrder: 0001,0000,0003,0006,0007
Boot0000* Syneto OS     HD(2,GPT,90486c99-677c-429e-830b-37474934819b,0x400800,0x12c000)/File(\EFI\rocky\shimx64.efi)
Boot0001* Syneto OS Backup        HD(1,GPT,34b15fe9-95bb-4d97-b791-291dce572448,0x800,0x12c000)/File(\EFI\rocky\shimx64.efi)
Boot0003* UEFI: Built-in EFI Shell      VenMedia(5023b95c-db26-429b-a648-bd47664c8012)..BO
Boot0006* (B4/D0/F0) UEFI PXE IPv4 Intel(R) Ethernet Controller X550(MAC:7CC255EB3758)  PciRoot(0x0)/Pci(0x10,0x0)/Pci(0x0,0x0)/MAC(7cc255eb3758,1)/IPv4(0.0.0.00.0.0.0,0,0)..BO
Boot0007* (B4/D0/F1) UEFI PXE IPv4 Intel(R) Ethernet Controller X550(MAC:7CC255EB3759)  PciRoot(0x0)/Pci(0x10,0x0)/Pci(0x0,0x1)/MAC(7cc255eb3759,1)/IPv4(0.0.0.00.0.0.0,0,0)..BO
MirrorStatus: Platform does not support address range mirror
DesiredMirroredPercentageAbove4G: 0.00
DesiredMirrorMemoryBelow4GB: false

Identify the two "Syneto OS" entries. One will reference a PARTUUID no longer present in lsblk — this is the old removed drive.

Step 2. List the drives and partitions to identify the differences

lsblk -o NAME,SIZE,MOUNTPOINT,PARTUUID

EXAMPLE OUTPUT

NAME           SIZE MOUNTPOINT PARTUUID 
zram0            4G [SWAP]     
nvme3n1        1.7T             
nvme0n1        1.7T             
nvme1n1        1.7T             
nvme2n1        1.7T             
nvme4n1        1.7T             
nvme7n1        1.7T             
nvme9n1      894.3G             
├─nvme9n1p1      2G             4a8807dd-c9ef-49a6-8bb0-49040b70ddb3 
│ └─md126        2G /boot      
├─nvme9n1p2    600M /boot/efi   90486c99-677c-429e-830b-37474934819b 
└─nvme9n1p3  195.3G             f033cf84-3a89-42e3-bd04-c823d15618f2 
 └─md127    195.2G /          
nvme8n1        1.7T             
nvme5n1        1.7T             
nvme6n1      894.3G             
├─nvme6n1p1    600M             e771da92-9132-4f34-bc20-258632af4603 
├─nvme6n1p2      2G             dda80697-1a96-4ace-8111-d495e155e0b7 
└─nvme6n1p3  195.3G             38b08ed6-2179-402a-aa81-1c58e7a1f7a5

PARTUUID present in both EFI and lsblk → healthy drive, do not touch
PARTUUID in EFI but not in lsblk → old removed drive, delete this entry
PARTUUID in lsblk but not in EFI → new drive, needs to be added

Step 3. Delete obsolete boot option

efibootmgr -b 0001 -B

Step 4. Confirm the obsolete entry was deleted

efibootmgr -v

EXAMPLE OUTPUT

BootCurrent: 0000 
Timeout: 1 seconds 
BootOrder: 0000,0003,0006,0007 
Boot0000* Syneto OS 
Boot0003* UEFI: Built-in EFI Shell 
Boot0006* (B4/D0/F0) UEFI PXE IPv4 Intel(R) Ethernet Controller X550(MAC:7CC255EB3758) 
Boot0007* (B4/D0/F1) UEFI PXE IPv4 Intel(R) Ethernet Controller X550(MAC:7CC255EB3759) 
MirrorStatus: Platform does not support address range mirror 
DesiredMirroredPercentageAbove4G: 0.00 
DesiredMirrorMemoryBelow4GB: false

Add New Boot Option for the New Drive

Run below command

efibootmgr -c \
  -d /dev/nvme6n1 \
  -p 1 \
  -L "Syneto OS Backup" \
  -l "\EFI\rocky\shimx64.efi"

EXAMPLE
BootCurrent: 0000
Timeout: 1 seconds
BootOrder: 0001,0000,0003,0006,0007
Boot0000* Syneto OS
Boot0003* UEFI: Built-in EFI Shell
Boot0006* (B4/D0/F0) UEFI PXE IPv4 Intel(R) Ethernet Controller X550(MAC:7CC255EB3758)
Boot0007* (B4/D0/F1) UEFI PXE IPv4 Intel(R) Ethernet Controller X550(MAC:7CC255EB3759)
Boot0001* Syneto OS Backup
MirrorStatus: Platform does not support address range mirror
DesiredMirroredPercentageAbove4G: 0.00
DesiredMirrorMemoryBelow4GB: false
Parameter Description

-d The drive device we added to the system and on which we created the partitions

-p The partition number for the EFI partition

-L The text in the EFI/BIOS boot options, to add the same name as the one we deleted.
There are only two options, so always make sure after the modifications to have the two expected options: "Syneto OS" and "Syneto OS Backup"

Ensure Correct Boot Order

Set the correct boot order

efibootmgr -o 0000,0001,0003,0006,0007

EXAMPLE

BootCurrent: 0000
Timeout: 1 seconds
BootOrder: 0000,0001,0003,0006,0007
Boot0000* Syneto OS
Boot0001* Syneto OS Backup
Boot0003* UEFI: Built-in EFI Shell
Boot0006* (B4/D0/F0) UEFI PXE IPv4 Intel(R) Ethernet Controller X550(MAC:7CC255EB3758)
Boot0007* (B4/D0/F1) UEFI PXE IPv4 Intel(R) Ethernet Controller X550(MAC:7CC255EB3759)
MirrorStatus: Platform does not support address range mirror
DesiredMirroredPercentageAbove4G: 0.00
DesiredMirrorMemoryBelow4GB: false

Copy the EFI Files to the New EFI Partition

Step 1. Verify the EFI partition on the healthy drive

If you're on SynetoOS 6.1 and above and /boot/efi is mounted from Drive 1:

blkid /dev/nvme9n1p2

If you're on SynetoOS 6.1 and above and /boot/efi is mounted from Drive 2:

blkid /dev/nvme6n1p1

Ensure both partitions show LABEL="EFI" and TYPE="vfat".

Step 2. Format the EFI partition if needed

If for any of the above the TYPE="vfat" value is different:

mkfs.vfat -F32 /dev/nvme6n1p1

Step 3. Verify drives are mounted

lsblk -o name,size,mountpoint

EXAMPLE OUTPUT

NAME      SIZE MOUNTPOINT
zram0       4G [SWAP]
nvme3n1     1.7T 
nvme0n1     1.7T 
nvme1n1     1.7T 
nvme2n1     1.7T 
nvme4n1     1.7T 
nvme7n1     1.7T 
nvme9n1   894.3G 
├─nvme9n1p1   2G 
│ └─md126     2G /boot
├─nvme9n1p2   600M /boot/efi
└─nvme9n1p3 195.3G 
 └─md127   195.2G /
nvme8n1     1.7T 
nvme5n1     1.7T 
nvme6n1   894.3G 
├─nvme6n1p1   600M 
├─nvme6n1p2   2G 
└─nvme6n1p3 195.3G

Step 4. Verify partitions are mounted

ls /boot/efi/**/**

EXAMPLE OUTPUT

/boot/efi/EFI/BOOT:
BOOTX64.EFI fbx64.efi

/boot/efi/EFI/rocky:
BOOTX64.CSV grub.cfg grubx64.efi mmx64.efi shim.efi shimx64-rocky.efi shimx64.efi

Step 5. Create a temporary mount point

mkdir -p /mnt/efi-backup

Step 6. Mount the EFI partition to the new drive

If you're on SynetoOS 6.1 and above and Drive 2 was replaced:

mount /dev/nvme6n1p1 /mnt/efi-backup

If you're on SynetoOS 6.1 and above and Drive 1 was replaced:

mount /dev/nvme9n1p1 /mnt/efi-backup

Step 7. Copy EFI contents

rsync -aHv /boot/efi/ /mnt/efi-backup/

Step 8. Commit the data to the disk

sync

EXAMPLE OUTPUT

sync

sending incremental file list
./
EFI/
EFI/BOOT/
EFI/BOOT/BOOTX64.EFI
EFI/BOOT/fbx64.efi
EFI/rocky/
EFI/rocky/BOOTX64.CSV
EFI/rocky/grub.cfg
EFI/rocky/grubx64.efi
EFI/rocky/mmx64.efi
EFI/rocky/shim.efi
EFI/rocky/shimx64-rocky.efi
EFI/rocky/shimx64.efi

sent 7,323,064 bytes received 210 bytes 14,646,548.00 bytes/sec
total size is 7,320,616 speedup is 1.00

Step 9. Verify files were copied successfully

ls /mnt/efi-backup/**/**

OUTPUT EXAMPLE

/mnt/efi-backup/EFI/BOOT:
BOOTX64.EFI fbx64.efi

/mnt/efi-backup/EFI/rocky:
BOOTX64.CSV grub.cfg grubx64.efi mmx64.efi shim.efi shimx64-rocky.efi shimx64.efi

Step 9. Unmount the partitions

umount /mnt/efi-backup

2 - If /boot/efi mounted from OS Drive 1, and OS Drive 1 broken/replaced:

Step 1. Ensure which are the new and old partitions

lsblk -o NAME,SIZE,MOUNTPOINT,SERIAL

EXAMPLE OUTPUT

[root@syneto-os admin]# lsblk -o NAME,SIZE,MOUNTPOINT,SERIAL
NAME            SIZE MOUNTPOINT SERIAL
zram0             4G [SWAP]     
nvme9n1       894.3G            S677NJ0R999999
├─nvme9n1p1     600M                  
├─nvme9n1p2       2G 
│ └─md126         2G /boot
└─nvme9n1p3   195.3G 
  └─md127     195.2G /
nvme6n1       894.3G            S465NY0M111111
├─nvme6n1p1     600M                       
├─nvme6n1p2       2G 
└─nvme6n1p3   195.3G

Step 2. Create the temporary source and destination mount points

mkdir -p /mnt/efi-source

mkdir -p /mnt/efi-dest

Step 3. Mount the old drive

mount /dev/nvme9n1p1 /mnt/efi-source

Step 4. Mount the new drive

mount /dev/nvme6n1p1 /mnt/efi-dest

Step 5. Copy source to destination content

rsync -aHv /mnt/efi-source/ /mnt/efi-dest/

Step 6. Commit the data to the disk

sync

Step 7. Ensure files were copied successfully

ls /mnt/efi-dest/**/**

EXAMPLE OUTPUT

/mnt/efi-dest/EFI/BOOT:
BOOTX64.EFI  fbx64.efi

/mnt/efi-dest/EFI/rocky:
BOOTX64.CSV  grub.cfg  grubx64.efi  mmx64.efi  shim.efi  shimx64-rocky.efi  shimx64.efi

Step 8. Unmount temporary mount points

umount /mnt/efi-source

umount /mnt/efi-dest

Step 9. Mount the EFI back to the live system location

mount /dev/nvme9n1p1 /boot/efi

Step 10. Confirm the system now sees the EFI partition correctly

lsblk | grep /boot/efi

EXAMPLE OUTPUT

[root@syneto-os ~]# lsblk | grep /boot/efi
└─nvme9n1p1 600M  0 part  /boot/efi

3 - If /boot/efi mounted from OS Drive 2, and OS Drive 1 broken/replaced:

Run below commands

blkid /dev/nvme6n1p1

EXAMPLE OUTPUT
/dev/nvme6n1p1: LABEL_FATBOOT="EFI" LABEL="EFI" UUID="8BDD-B465" TYPE="vfat" PARTLABEL="EFI" PARTUUID="e771da92-9132-4f34-bc20-258632af4603"
Ensure these values are exactly as in the example below:

LABEL_FATBOOT="EFI"

LABEL="EFI"

TYPE="vfat"

blkid /dev/nvme9n1p1

EXAMPLE OUTPUT
/dev/nvme9n1p1: LABEL_FATBOOT="EFI" LABEL="EFI" UUID="8CFD-CE0A" TYPE="vfat" PARTUUID="90486c99-677c-429e-830b-37474934819b"
Ensure these values are exactly as in the example below:

LABEL_FATBOOT="EFI"

LABEL="EFI"

TYPE="vfat"

Step 1 (optional). Format if for any of the above the TYPE="vfat" value is different

mkfs.vfat -F32 /dev/nvme6n1p1

Step 2. Ensure drives were mounted successfully

lsblk -o name,size,mountpoint

EXAMPLE OUTPUT

NAME      SIZE MOUNTPOINT
nvme9n1   894.3G 
├─nvme9n1p1   600M /boot/efi 
├─nvme9n1p2     2G /boot
└─nvme9n1p3 195.3G /
nvme6n1   894.3G 
├─nvme6n1p1   600M      
├─nvme6n1p2     2G 
└─nvme6n1p3 195.3G

Step 3. Ensure partitions were mounted successfully

ls /boot/efi/**/**

EXAMPLE OUTPUT

/boot/efi/EFI/BOOT:
BOOTX64.EFI fbx64.efi

/boot/efi/EFI/rocky:
BOOTX64.CSV grub.cfg grubx64.efi mmx64.efi shim.efi shimx64-rocky.efi shimx64.efi

Step 4. Create a temporary mount point

mkdir -p /mnt/efi-backup

Step 5. Mount the EFI partition to the new drive

mount /dev/nvme6n1p1 /mnt/efi-backup

Step 6. Copy EFI contents

rsync -aHv /boot/efi/ /mnt/efi-backup/

Step 7. Commit the data to the disk

sync

EXAMPLE OUTPUT

sync

sending incremental file list
./
EFI/
EFI/BOOT/
EFI/BOOT/BOOTX64.EFI
EFI/BOOT/fbx64.efi
EFI/rocky/
EFI/rocky/BOOTX64.CSV
EFI/rocky/grub.cfg
EFI/rocky/grubx64.efi
EFI/rocky/mmx64.efi
EFI/rocky/shim.efi
EFI/rocky/shimx64-rocky.efi
EFI/rocky/shimx64.efi

sent 7,323,064 bytes received 210 bytes 14,646,548.00 bytes/sec
total size is 7,320,616 speedup is 1.00

Step 8. Ensure files were copied successfully

ls /mnt/efi-backup/**/**

Output should be identical with output from step 3

/mnt/efi-backup/EFI/BOOT:
BOOTX64.EFI fbx64.efi

/mnt/efi-backup/EFI/rocky:
BOOTX64.CSV grub.cfg grubx64.efi mmx64.efi shim.efi shimx64-rocky.efi shimx64.efi

Step 9. Unmount the partitions

umount /mnt/efi-backup

Health Checks

Step 1. List details for both devices

mdadm --detail /dev/md126 /dev/md127

EXAMPLE OUTPUT

/dev/md126: 
          Version : 1.2 
    Creation Time : Thu Dec 11 12:11:10 2025 
       Raid Level : raid1 
       Array Size : 2094080 (2045.00 MiB 2144.34 MB) 
    Used Dev Size : 2094080 (2045.00 MiB 2144.34 MB) 
     Raid Devices : 2 
    Total Devices : 2 
      Persistence : Superblock is persistent 
   
    Intent Bitmap : Internal 
   
      Update Time : Fri Dec 19 09:51:50 2025 
            State : clean  
   Active Devices : 2 
  Working Devices : 2 
    Failed Devices : 0 
    Spare Devices : 0 
   
  Consistency Policy : bitmap 
   
            Name : localhost.localdomain:boot 
            UUID : 54b841c1:af2f0102:562ecbcb:3e32dd0f 
          Events : 193 
   
    Number  Major  Minor  RaidDevice State 
          2    259      12        0      active sync  /dev/nvme6n1p2 
          1    259      11        1      active sync  /dev/nvme9n1p1 
/dev/md127: 
          Version : 1.2 
    Creation Time : Thu Dec 11 12:11:15 2025 
       Raid Level : raid1 
       Array Size : 204667904 (195.19 GiB 209.58 GB) 
    Used Dev Size : 204667904 (195.19 GiB 209.58 GB) 
     Raid Devices : 2 
    Total Devices : 2 
      Persistence : Superblock is persistent 
   
    Intent Bitmap : Internal 
   
      Update Time : Fri Dec 19 10:31:53 2025 
            State : active  
   Active Devices : 2 
  Working Devices : 2 
    Failed Devices : 0 
    Spare Devices : 0 
   
  Consistency Policy : bitmap 
   
            Name : localhost.localdomain:root 
            UUID : a6358b5a:8bcb6700:2a5188ff:6100fcb2 
          Events : 379712 
   
    Number  Major  Minor  RaidDevice State 
          3    259      14        0      active sync  /dev/nvme6n1p3 
          2    259      15        1      active sync  /dev/nvme9n1p3

Ensure:

2 devices in each RAID
RAID type is raid1
Both partitions in state active sync
md126 ≈ 2 GB, md127 ≈ 200 GB
State is clean or active only — no degraded, rebuilding, etc.

Step 2. Verify EFI partition content matches

diff -rq /boot/efi /mnt/efi-backup

Command should return no value

Step 3. Launch a dry-run checksum comparison

rsync -n -avc /boot/efi/ /mnt/efi-backup/

EXAMPLE OUTPUT
sending incremental file list 
./ 
EFI/ 
EFI/BOOT/ 
EFI/rocky/ 
 
sent 464 bytes received 58 bytes 1,044.00 bytes/sec 
total size is 7,320,616 speedup is 14,024.17 (DRY RUN)
Only directory names should appear in the output — no individual files.

Step 4. Find the "Syneto OS" boot entry

lsblk -o NAME,SIZE,MOUNTPOINT,PARTUUID | grep -i "$(efibootmgr -v | grep -m1 -E "Syneto OS\s+HD" | awk -F, '{print $3}')"

EXAMPLE OUTPUT

├─nvme9n1p2   600M /boot/efi       90486c99-677c-429e-830b-37474934819b

Step 5. Find the "Syneto OS Backup" boot entry

lsblk -o NAME,SIZE,MOUNTPOINT,PARTUUID | grep -i "$(efibootmgr -v | grep -m1 -E "Syneto OS Backup\s+HD" | awk -F, '{print $3}')"

EXAMPLE OUTPUT

├─nvme6n1p1   600M /mnt/efi-backup e771da92-9132-4f34-bc20-258632af4603

Step 6. Confirm correct boot order

efibootmgr

EXAMPLE OUTPUT

BootCurrent: 0000 
Timeout: 1 seconds 
BootOrder: 0000,0001,0003,0006,0007 
Boot0000* Syneto OS 
Boot0001* Syneto OS Backup 
Boot0003* UEFI: Built-in EFI Shell 
Boot0006* (B4/D0/F0) UEFI PXE IPv4 Intel(R) Ethernet Controller X550(MAC:7CC255EB3758) 
Boot0007* (B4/D0/F1) UEFI PXE IPv4 Intel(R) Ethernet Controller X550(MAC:7CC255EB3759) 
MirrorStatus: Platform does not support address range mirror 
DesiredMirroredPercentageAbove4G: 0.00 
DesiredMirrorMemoryBelow4GB: false

First two entries in BootOrder must be Syneto OS then Syneto OS Backup.

Step 7. Reboot to confirm the operation completed successfully

Parameter	Description
-d	The drive device we added to the system and on which we created the partitions
-p	The partition number for the EFI partition
-L	The text in the EFI/BIOS boot options, to add the same name as the one we deleted. There are only two options, so always make sure after the modifications to have the two expected options: "Syneto OS" and "Syneto OS Backup"

Syneto Knowledge

Identify the new drive

Create partitions

Reload Partitions

Recreate MD RAID

Add Missing Devices to MD RAID

Restore EFI Boot Loader Mirroring

Add New Boot Option for the New Drive

Ensure Correct Boot Order

Copy the EFI Files to the New EFI Partition

Health Checks

Related Articles