Replace Storage Group 1x4TB hdd with 1x8TB hdd finish as Unutilized Space

lmib2006 · January 25, 2026, 6:26pm

Hello, I have a QNAP TS-464 with QTS 5.2.8 and 3 x 4TB hdd.

Does not have any Raid configurations, instead have a Storage Pool for each individual hdd.

One of those drives begin to have SMART Reading Test Failures but still operating OK.

Got a new 8TB hdd and make to replace it and made the following steps:

0.- Backup of the data of Storage Pool and backup /mnt/HDA_ROOT/.config/raid.conf file

1.- Expand the Storage Pool 4 with the New 8TB to RAID1 y wait RAID SYNC

[/mnt/HDA_ROOT/.config] # mdadm --query --detail /dev/md4
/dev/md4:
Version : 1.0
Creation Time : Sat Dec 9 18:27:53 2017
Raid Level : raid1
Array Size : 3897063616 (3716.53 GiB 3990.59 GB)
Used Dev Size : 3897063616 (3716.53 GiB 3990.59 GB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent

Update Time : Sat Jan 24 00:37:28 2026
      State : clean, degraded, recovering

Active Devices : 1
Working Devices : 2
Failed Devices : 0
Spare Devices : 1

Rebuild Status : 84% complete

       Name : 4
       UUID : 402f5267:ef7841b7:da5e95e1:ada6659a
     Events : 7674

Number   Major   Minor   RaidDevice State
   2       8       19        0      active sync   /dev/sdb3		BAD 4TB
   1       8        3        1      spare rebuilding   /dev/sda3	NEW 8TB

2.- After expansion and RAID Sync OK, force Fail the 4TB hdd

mdadm /dev/md4 --fail /dev/sdb3
mdadm /dev/md4 --remove /dev/sdb3

[/mnt/HDA_ROOT/.config] # mdadm /dev/md4 --fail /dev/sdb3
mdadm: set /dev/sdb3 faulty in /dev/md4

[/mnt/HDA_ROOT/.config] # mdadm /dev/md4 --remove /dev/sdb3
mdadm: hot removed /dev/sdb3 from /dev/md4

[/mnt/HDA_ROOT/.config] # mdadm --query --detail /dev/md4
/dev/md4:
Version : 1.0
Creation Time : Sat Dec  9 18:27:53 2017
Raid Level : raid1
Array Size : 3897063616 (3716.53 GiB 3990.59 GB)
Used Dev Size : 3897063616 (3716.53 GiB 3990.59 GB)
Raid Devices : 2
Total Devices : 1
Persistence : Superblock is persistent

Update Time : Sat Jan 24 20:47:18 2026
      State : clean, degraded 

Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0

       Name : 4
       UUID : 402f5267:ef7841b7:da5e95e1:ada6659a
     Events : 7700

Number   Major   Minor   RaidDevice State
   0       0        0        0      removed
   1       8        3        1      active sync   /dev/sda3

3.- Expanded the RAID size to 8TB

/mnt/HDA_ROOT/.config] # mdadm --query --detail /dev/md4
/dev/md4:
Version : 1.0
Creation Time : Sat Dec  9 18:27:53 2017
Raid Level : raid1
Array Size : 3897063616 (3716.53 GiB 3990.59 GB)	<<<<< RAID SIZE
Used Dev Size : 3897063616 (3716.53 GiB 3990.59 GB)
Raid Devices : 2
Total Devices : 1
Persistence : Superblock is persistent

Update Time : Sat Jan 24 20:47:18 2026
      State : clean, degraded 

Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0

       Name : 4
       UUID : 402f5267:ef7841b7:da5e95e1:ada6659a
     Events : 7700

Number   Major   Minor   RaidDevice State
   0       0        0        0      removed
   1       8        3        1      active sync   /dev/sda3

[/mnt/HDA_ROOT/.config] # mdadm -E /dev/sda3
/dev/sda3:
Magic : a92b4efc
Version : 1.0
Feature Map : 0x0
Array UUID : 402f5267:ef7841b7:da5e95e1:ada6659a
Name : 4
Creation Time : Sat Dec  9 18:27:53 2017
Raid Level : raid1
Raid Devices : 2

Avail Dev Size : 15608143592 (7442.54 GiB 7991.37 GB)	<<<<< DISK SIZE <<<<< (*1)
Array Size : 3897063616 (3716.53 GiB 3990.59 GB)	<<<<< RAID SIZE
Used Dev Size : 7794127232 (3716.53 GiB 3990.59 GB)
Super Offset : 15608143856 sectors
Unused Space : before=0 sectors, after=7814016624 sectors
State : clean
Device UUID : 7bf44b7f:395b58fa:c732229c:d377cec2

Update Time : Sat Jan 24 20:47:18 2026
   Checksum : f52604fb - correct
     Events : 7700

Device Role : Active device 1
Array State : .A (‘A’ == active, ‘.’ == missing, ‘R’ == replacing)

NEW RAID SIZE = 7442.54 GiB(*1) por 1.000.000

7442.54 GiB x 1.000.000 = 7442540000

mdadm --grow /dev/md4 --size=7442540000

[/mnt/HDA_ROOT/.config] # mdadm --grow /dev/md4 --size=7442540000
mdadm: component size of /dev/md4 has been set to 7442540000K

4.- Now the RAID size is 8TB

[/mnt/HDA_ROOT/.config] # mdadm --query --detail /dev/md4
/dev/md4:
Version : 1.0
Creation Time : Sat Dec 9 18:27:53 2017
Raid Level : raid1
Array Size : 7442540000 (7097.76 GiB 7621.16 GB)
Used Dev Size : 7442540000 (7097.76 GiB 7621.16 GB)
Raid Devices : 2
Total Devices : 1
Persistence : Superblock is persistent

Update Time : Sat Jan 24 21:08:53 2026
      State : clean, degraded

Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0

       Name : 4
       UUID : 402f5267:ef7841b7:da5e95e1:ada6659a
     Events : 7703

Number   Major   Minor   RaidDevice State
   0       0        0        0      removed
   1       8        3        1      active sync   /dev/sda3

5.- Increase the PVSize to the new Disk

[/mnt/HDA_ROOT/.config] # pvdisplay

WARNING: duplicate PV L0khUDWnb5y7IVDuV2cawm9IrQnNLccT is being used from both devices /dev/drbd4 and /dev/md4
Found duplicate PV L0khUDWnb5y7IVDuV2cawm9IrQnNLccT: using existing dev /dev/drbd4
— Physical volume —
PV Name               /dev/drbd4
VG Name               vg4
PV Size               3.63 TiB / not usable 1.15 MiB
Allocatable           yes (but full)
PE Size               4.00 MiB
Total PE              951431
Free PE               0
Allocated PE          951431
PV UUID               L0khUD-Wnb5-y7IV-DuV2-cawm-9IrQ-nNLccT

[/mnt/HDA_ROOT/.config] # pvresize /dev/md4

WARNING: duplicate PV L0khUDWnb5y7IVDuV2cawm9IrQnNLccT is being used from both devices /dev/drbd4 and /dev/md4
Found duplicate PV L0khUDWnb5y7IVDuV2cawm9IrQnNLccT: using existing dev /dev/drbd4
Physical volume “/dev/drbd4” changed
1 physical volume(s) resized / 0 physical volume(s) not resized

[/mnt/HDA_ROOT/.config] # pvdisplay

— Physical volume —
PV Name               /dev/drbd4
VG Name               vg4
PV Size               6.93 TiB / not usable 2.43 MiB
Allocatable           yes
PE Size               4.00 MiB
Total PE              1817025
Free PE               865594
Allocated PE          951431
PV UUID               L0khUD-Wnb5-y7IV-DuV2-cawm-9IrQ-nNLccT

6.- Reduce the RAID1 member on the Storage Pool to 1 (the new disk)

mdadm --grow /dev/md4 --raid-devices=1 --force

7.- Modify the file /mnt/HDA_ROOT/.config/raid.conf to update the serial number of the HDD in RAID 4 entry

8.- TurnOFF QNAP and replace 4TB hdd (put in failed before) with the 8TB hdd

9.- TurnON QNAP

At this point, I have access to Storage Pool, but the extra space from the new 8TB hdd is maked ad Unutilized:

Try to expand Storage Pool 4 and cannot find the way. The GUI Expand option expects an aditional hdd.

By command line, i found that the tier-thin-pool asosiated to the VG4 still in 4TB and I an unable to expand it:

[/mnt/HDA_ROOT/.config] # vgdisplay vg4
— Volume group —
VG Name vg4
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 35045
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 10
Open LV 8
Max PV 0
Cur PV 1
Act PV 1
VG Size 6.93 TiB
PE Size 4.00 MiB
Total PE 1817025
Alloc PE / Size 951431 / 3.63 TiB
Free PE / Size 865594 / 3.30 TiB
VG UUID YkD33l-vSbL-kNBJ-yRMU-nWME-dRXI-fo7UYd

[/mnt/HDA_ROOT/.config] # lvs -a -o +segtype | grep vg4
WARNING: duplicate PV XpYo4Q8CP2wXSdhWZbAjjkJLiVBhRPhd is being used from both devices /dev/drbd1 and /dev/md1
Found duplicate PV XpYo4Q8CP2wXSdhWZbAjjkJLiVBhRPhd: using /dev/drbd1 not /dev/md1
Using duplicate PV /dev/drbd1 from subsystem DRBD, ignoring /dev/md1
WARNING: duplicate PV pcPuLdqUE3ByQGWDma2qWU0LNbUrNXOY is being used from both devices /dev/drbd2 and /dev/md2
Found duplicate PV pcPuLdqUE3ByQGWDma2qWU0LNbUrNXOY: using existing dev /dev/drbd2
WARNING: duplicate PV ixbtdqEUyAcJKbE8sV884nrDQKn9igJu is being used from both devices /dev/drbd5 and /dev/md5
Found duplicate PV ixbtdqEUyAcJKbE8sV884nrDQKn9igJu: using existing dev /dev/drbd5
lv10 vg4 Vwi-aot— 150.00g tp4 100.00 thick
lv11 vg4 Vwi-aot— 273.25g tp4 100.00 thick
lv12 vg4 Vwi-aot— 750.00g tp4 100.00 thick
lv1315 vg4 -wi-ao---- 380.00m linear
lv2 vg4 Vwi-aot— 100.00g tp4 100.00 thick
lv3 vg4 Vwi-aot— 5.00g tp4 99.92 thick
lv5 vg4 Vwi-aot— 325.50g tp4 100.00 thick
lv547 vg4 -wi------- 36.79g linear
lv9 vg4 Vwi-aot— 1.87t tp4 100.00 thick
tp4 vg4 twi-aot— 3.53t 97.37 0.37 tier-thin-pool
[tp4_tierdata_0] vg4 vwi-aov— 4.00m zero
[tp4_tierdata_1] vg4 vwi-aov— 4.00m zero
[tp4_tierdata_2] vg4 Twi-ao---- 3.53t linear
[tp4_tmeta] vg4 ewi-ao---- 64.00g linear

[/mnt/HDA_ROOT/.config] # lvextend -l +100%FREE --use-policies /dev/vg4/tp4
Please specify the target tier to extend
Run `lvextend --help’ for more information.

[/mnt/HDA_ROOT/.config] # lvextend -l +100%FREE /dev/vg4/tp4_tierdata_2
Can’t resize internal logical volume tp4_tierdata_2
Run `lvextend --help’ for more information.

Has any of you tried replacing a disk with a larger one without backing up to an external USB disk and recreating the storage pool from scratch?

I understand that if the storage pool had two disks in RAID1, I would have the option to Replace Disk One by One, but in this case I want to keep only one disk with expanded capacity.

Thank you in advance for any help you can give me, and sorry for the long post

Regards

LM

NA9D · January 25, 2026, 7:34pm

I am like so confused why you think it is a good idea to try to “Linux” it yourself instead of using QNAPs user interface and tools.

You’ve likely messed things up. You did not have a RAID originally but 4 different storage pools. What was your plan to do with the 8TB drive?

You can’t have an 8TB raid with a single drive.

I’m so confused with what you thought was an appropriate thing to do…

lmib2006 · January 25, 2026, 7:59pm

Good evening, @NA9D, and thank you for taking the time to read my post. My idea was not to build a RAID1, but to use RAID1 to clone the disk I want to replace.

Using the QNAP GUI interface, I don’t have this capability for a single-disk Storage Pool. QNAP offers the option to replace all disks in a RAID with higher-capacity disks (Replace Disk One by One), but it must be a Storage Pool in Raid 1 or Raid 5/6.

In the past, I have replaced disks in my Storage Pool using this technique:

Single Disk Storage Pool (Old Disk to be replaced) → RAID1 (Old Disk + New Disk) → Single Disk Storage Pool (New Disk).

This procedure (a little tricky because you need to modify the /mnt/HDA_ROOT/.config/raid.conf file) works perfectly if the disk size of the new disk is maintained. This time I tried using a higher capacity new disk.

Clearly, at the RAID1 level, the size keeps to the smaller disk, but I thought it would be relatively easy to expand the Storage Pool once I was left with only the new disk. This is where I am now, unable to find a way for QNAP to detect the new space available on the 8TB disk.

Regards

NA9D · January 25, 2026, 9:13pm

Uhm…

Why not just stick the new drive in, create a new storage space on that drive and copy the data from one drive to the other. Much safer than all the gymnastics you went through. And now you can use all 8TB of your new disk.

I’m still confused why you did it that way.

There is no way for your to utilize that other 4TB because the QNAP thinks you are in RAID1 with another 4TB disk. You can’t expand it.