I have an F4-424 Pro (TOS6) with two 500 GB SSDs and four 1 TB HDDs. I created two volumes with TRAID type: the first one on SSDs, the second one on HDDs. So initially I had:
md0 - RAID1 sdza4 + sdzb4 → vg0-lv0
md1 - RAID5 sda4 + sdb4 + sdc4 + sdd4 → vg1-lv1
md8 - RAID1 (swap) sdza3 + sdzb3
md9 - RAID1 (system) sdza2 + sdzb2
Then I started to replace the HDDs one by one to extend the vg1-lv1 size (as described here: viewtopic.php?t=8036 — Online Array Expansion).
I shut down the NAS, replaced one HDD, booted, selected online raid capacity expansion, waited, etc.
After replacing the first HDD with a 6 TB one — all OK.
After the second — md1 recovered, and md2 (RAID1: sdc5 + sdd5) was created and added to vg1-lv1.
After the third — I expected md1 to recover again, and md2 to convert to RAID5 with sdb5 + sdc5 + sdd5.
But from that moment a strange thing happened — the MD devices changed order:
md0 - RAID5 sda4 + sdb4 + sdc4 + sdd4 → vg1-lv1
md1 - RAID5 sdb5 + sdc5 + sdd5 → vg1-lv1
md2 - RAID1 sdza4 + sdzb4 → vg0-lv0
And here is the current state:
Code: Select all
# cat /proc/mdstat
md2 : active raid1 sdzb4[0] sdza4[1]
477855888 blocks super 1.2 [2/2] [UU]
bitmap: 2/4 pages [8KB], 65536KB chunk
md1 : active raid5 sdc5[0] sdb5[2] sdd5[1]
4883829012 blocks super 1.2 level 5, 4k chunk, algorithm 2 [3/3] [UUU]
resync=DELAYED
md0 : active raid5 sda4[0] sdd4[3] sdc4[4] sdb4[5]
2898410496 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [U_UU]
[=====>...............] recovery = 27.5% (266298900/966136832) finish=78.8min speed=147867K/sec
bitmap: 2/8 pages [8KB], 65536KB chunk
...
# lsblk -f
NAME FSTYPE FSVER LABEL UUID FSAVAIL FSUSE% MOUNTPOINTS
sda
├─sda1
├─sda2
├─sda3
└─sda4 linux_raid_member 1.2 DellsTNASpro:UTOSUSER-X86-S64 38c2cf39-99d9-f61c-02dc-822b469f1df3
└─md0 LVM2_member LVM2 001 YuHMGq-AVoe-ajkK-h8pP-mSgb-22qi-Fadfc2
└─vg1-lv1 btrfs TOS_VOL_20250805 16ca49ac-85be-475f-a256-70f6654c7a51 4.7T 35% /Volume2
/var/subvols/8vEbTxkKvwb
sdb
├─sdb1
├─sdb2
├─sdb3
├─sdb4 linux_raid_member 1.2 DellsTNASpro:UTOSUSER-X86-S64 38c2cf39-99d9-f61c-02dc-822b469f1df3
│ └─md0 LVM2_member LVM2 001 YuHMGq-AVoe-ajkK-h8pP-mSgb-22qi-Fadfc2
│ └─vg1-lv1 btrfs TOS_VOL_20250805 16ca49ac-85be-475f-a256-70f6654c7a51 4.7T 35% /Volume2
│ /var/subvols/8vEbTxkKvwb
└─sdb5 linux_raid_member 1.2 DellsTNASpro:UTOSUSER-X86-S64 1acd9f64-5a36-edb0-22d8-382b3f3f9644
└─md1 LVM2_member LVM2 001 pD6v30-kk9f-Qv7k-36IR-1tdu-knfj-7aoly2
└─vg1-lv1 btrfs TOS_VOL_20250805 16ca49ac-85be-475f-a256-70f6654c7a51 4.7T 35% /Volume2
/var/subvols/8vEbTxkKvwb
sdc
├─sdc1
├─sdc2
├─sdc3
├─sdc4 linux_raid_member 1.2 DellsTNASpro:UTOSUSER-X86-S64 38c2cf39-99d9-f61c-02dc-822b469f1df3
│ └─md0 LVM2_member LVM2 001 YuHMGq-AVoe-ajkK-h8pP-mSgb-22qi-Fadfc2
│ └─vg1-lv1 btrfs TOS_VOL_20250805 16ca49ac-85be-475f-a256-70f6654c7a51 4.7T 35% /Volume2
│ /var/subvols/8vEbTxkKvwb
└─sdc5 linux_raid_member 1.2 DellsTNASpro:UTOSUSER-X86-S64 1acd9f64-5a36-edb0-22d8-382b3f3f9644
└─md1 LVM2_member LVM2 001 pD6v30-kk9f-Qv7k-36IR-1tdu-knfj-7aoly2
└─vg1-lv1 btrfs TOS_VOL_20250805 16ca49ac-85be-475f-a256-70f6654c7a51 4.7T 35% /Volume2
/var/subvols/8vEbTxkKvwb
sdd
├─sdd1
├─sdd2
├─sdd3
├─sdd4 linux_raid_member 1.2 DellsTNASpro:UTOSUSER-X86-S64 38c2cf39-99d9-f61c-02dc-822b469f1df3
│ └─md0 LVM2_member LVM2 001 YuHMGq-AVoe-ajkK-h8pP-mSgb-22qi-Fadfc2
│ └─vg1-lv1 btrfs TOS_VOL_20250805 16ca49ac-85be-475f-a256-70f6654c7a51 4.7T 35% /Volume2
│ /var/subvols/8vEbTxkKvwb
└─sdd5 linux_raid_member 1.2 DellsTNASpro:UTOSUSER-X86-S64 1acd9f64-5a36-edb0-22d8-382b3f3f9644
└─md1 LVM2_member LVM2 001 pD6v30-kk9f-Qv7k-36IR-1tdu-knfj-7aoly2
└─vg1-lv1 btrfs TOS_VOL_20250805 16ca49ac-85be-475f-a256-70f6654c7a51 4.7T 35% /Volume2
/var/subvols/8vEbTxkKvwb
sdzb
├─sdzb1 vfat FAT32 UTOSDISK 5395-0076
├─sdzb2 linux_raid_member 1.2 TNAS:UTOSCORE-X86-S64 b3764bc5-9273-a39e-4aac-545f4d945971
│ └─md9 ext4 1.0 780ba0e8-d1c3-4ae7-a765-bc9ef707dbee 5.1G 26% /
├─sdzb3 linux_raid_member 1.2 TNAS:UTOSSWAP-X86-S64 586a539e-2fd7-048b-661c-f37166d2f05a
│ └─md8 swap 1 4d9a1bd2-09fa-42f7-96f5-b2eb5fc09af4 [SWAP]
└─sdzb4 linux_raid_member 1.2 DellsTNASpro:UTOSUSER-X86-S64 7c6186b8-28e3-5072-dd70-052dcda714ec
└─md2 LVM2_member LVM2 001 5UHuUh-B1qg-Q0bY-pFKk-ORu3-kdKg-Q2NGaX
└─vg0-lv0 btrfs TOS_VOL_20250805 12970f5d-15e8-40de-8376-e9283a275486 447.1G 1% /Volume1/homes/user/MOD_CONFIG
/home/user/MOD_CONFIG
/usr/local/@APP_CONFIG
/usr/local/@APP_CONFIG
/home
/Volume1
/var/subvols/8vEbTxkKvwa
sdza
├─sdza1 vfat FAT32 UTOSDISK 539B-EC3C
├─sdza2 linux_raid_member 1.2 TNAS:UTOSCORE-X86-S64 b3764bc5-9273-a39e-4aac-545f4d945971
│ └─md9 ext4 1.0 780ba0e8-d1c3-4ae7-a765-bc9ef707dbee 5.1G 26% /
├─sdza3 linux_raid_member 1.2 TNAS:UTOSSWAP-X86-S64 586a539e-2fd7-048b-661c-f37166d2f05a
│ └─md8 swap 1 4d9a1bd2-09fa-42f7-96f5-b2eb5fc09af4 [SWAP]
└─sdza4 linux_raid_member 1.2 DellsTNASpro:UTOSUSER-X86-S64 7c6186b8-28e3-5072-dd70-052dcda714ec
└─md2 LVM2_member LVM2 001 5UHuUh-B1qg-Q0bY-pFKk-ORu3-kdKg-Q2NGaX
└─vg0-lv0 btrfs TOS_VOL_20250805 12970f5d-15e8-40de-8376-e9283a275486 447.1G 1% /Volume1/homes/user/MOD_CONFIG
/home/user/MOD_CONFIG
/usr/local/@APP_CONFIG
/usr/local/@APP_CONFIG
/home
/Volume1
/var/subvols/8vEbTxkKvwa
1. Is it OK that the MD order changed?
On the forum I often see md0 tied to vg0-lv0, and md1 to vg1-lv1.
Could this reordering cause problems with system logic or updates?
2. If this is a problem — how do I fix the order?
I tried editing /etc/mdadm/mdadm.conf and /etc/mdadm.conf on another NAS (F4-212), but both files get overwritten after reboot.
So I guess some logic sets the order, but I don’t know where it lives or how to override it.
3. What will happen when I replace the fourth (last) HDD with an 8 TB one?
I expect a new md3 to appear and be added to vg1-lv1, but since md2 is already used for SSDs, could this cause conflicts?
Or will the system handle it correctly anyway?
Thanks in advance for any help or clarification!
