Missing Pool - state is OFFLINE

[Ogrebear]

My TrueNAS is on 25.10.0.1 running on a Intel Core i5-6500

There are six disks and an NVME boot disks all connected directly to the motherboard.

This was working fine until recently when I started getting:

Critical
Pool AntecNAS state is OFFLINE: None

In the notfications and email. I checked the system and it seems to have lost 2 drives from the disk list and the Pool has gone missing. I cannot access any data via SMB now.

The remaining disks all say there is no errors.

The Import Pool option does not list my previous pool AntecNAS

Going to Shell, I get this on a zpool import:

truenas_admin@truenas[~]$ sudo zpool import
[sudo] password for truenas_admin:
pool: AntecNAS
id: 7002117372825943148
state: UNAVAIL
status: One or more devices contains corrupted data.
action: The pool cannot be imported due to damaged devices or data.
see:
config:

    AntecNAS                                  UNAVAIL  insufficient replicas
      raidz1-0                                UNAVAIL  insufficient replicas
        977618a3-2d65-4b37-bdfd-9052136162e0  ONLINE
        0ced0fb0-b232-413b-8c60-ecd325a11a44  ONLINE
        bc82ff2e-9028-4d32-b269-896916639c4e  ONLINE
        8837ab81-6e7c-4778-8e83-6df850a5c256  UNAVAIL
        068b5935-6869-4df8-8f93-ee6b1f0bce80  ONLINE
        f7db8546-43d7-4b99-a04b-dec9b3ec0f2a  UNAVAIL

Status is telling me this:

truenas_admin@truenas[~]$ zpool status -v
pool: boot-pool
state: ONLINE
scan: scrub repaired 0B in 00:00:18 with 0 errors on Fri May 1 03:45:19 2026
config:

    NAME         STATE     READ WRITE CKSUM
    boot-pool    ONLINE       0     0     0
      nvme0n1p3  ONLINE       0     0     0

And this is the output from a lsblk:

truenas_admin@truenas[~]$ sudo lsblk -b -o NAME,MODEL,ROTA,PTTYPE,TYPE,START,SIZE,PARTTYPENAME,PARTUUID
NAME MODEL ROTA PTTYPE TYPE START SIZE PARTTYPENAME PARTUUID
sda WDC WD20EZRX-00DC0B0 1 gpt disk 2000398934016
└─sda1 1 gpt part 2048 1998251360256 Solaris /usr & Apple ZFS 977618a3-2d65-4b37-bdfd-9052136162e0
sdb ST2000DM001-1ER164 1 gpt disk 2000398934016
└─sdb1 1 gpt part 2048 1998251360256 Solaris /usr & Apple ZFS 0ced0fb0-b232-413b-8c60-ecd325a11a44
sdc ST2000DM001-1ER164 1 gpt disk 2000398934016
└─sdc1 1 gpt part 2048 1998251360256 Solaris /usr & Apple ZFS bc82ff2e-9028-4d32-b269-896916639c4e
sdd ST2000DM001-1ER164 1 gpt disk 2000398934016
└─sdd1 1 gpt part 2048 1998251360256 Solaris /usr & Apple ZFS 068b5935-6869-4df8-8f93-ee6b1f0bce80
nvme0n1 CL1-3D256-Q11 NVMe SSSTC 256GB 0 gpt disk 256060514304
├─nvme0n1p1 0 gpt part 4096 1048576 BIOS boot 13fbf068-acc0-4eac-8265-1212aa0e7752
├─nvme0n1p2 0 gpt part 6144 536870912 EFI System 73b4d94d-1f91-4e0c-a2ef-881361952c2e
└─nvme0n1p3 0 gpt part 1054720 255520480768 Solaris /usr & Apple ZFS a79220fe-e613-4548-b11f-5aa2577cf9bc

I would like to recover the data from the Pool as it seems the backup drive I had has failed too.

No idea of any external cause, my place does not seem to have had any power cuts recently.

Have not pulled the seemingly two dead drives for now.

Please help.

[SmallBarky]

Bad News. Two dead drives in a Raid-Z1 pool means you lost the entire pool and data. You would need to get at least one of the two offline drives to come back to healthy.

I would power down and check all the physical cables / connections and then try booting back up.

[Arwen]

Agree with @SmallBarky, you need to get 1 of the failed disks back. Or your data is lost.

@Ogrebear

my place does not seem to have had any power cuts

Power problems can cause hardware, like disks, to fail.

However, ZFS was specifically designed NOT to loose data on power loss, (or OS crash):

ZFS pools & power loss - you won't lose data

There is sometimes misconceptions about ZFS losing data due to power loss. The subject of power loss, (or OS crash), and then not being able to import a ZFS pool comes up here in the forums a few times a month. Here is the skinny on what should happen. There are several things to un-pack about power loss affecting ZFS and data loss. Any previously stored data in a ZFS pool can not be / is not lost on power loss. Exception is in hardware failures that affect pool redundancy. Like the loss of b…

[Farout]

If you cant bring at least one drive back online, and have no backups, you best bet is on a Recovery Software such as UFS Explorer or Klennet. Both are Windows programs.

[etorix]

UFS Explorer is also available for macOS and Linux. But I suspect that the license is not palatable when it comes to recover from a pool of old 2 TB HDDs.

So it all comes to resurrecting at least one of the failed drives. And having enough external drive space to recover and/or make full sector copies of the failing drives.
Can you hear them spin when powered?
Do they show up upon boot, even briefly? (If so, putting drives in the cold might help.)

[Ogrebear]

Checking in the BIOS SATA 3 and SATA 5 are coming up as ‘Not Installed’ so the BIOS is not even reading them. I will pull the drives from the system and see if I can spin them up in a caddy.

[Ogrebear]

Both drives spin up fine in a caddy, and CrystalDiskInfo rates them ‘good’ - no errors.

I am wondering it is the board in the NAS machine maybe?

Can I unplug the other SATA’s and use different sockets for these two drives? Is FreeNAS likely to bring the pool online if I do?

[SmallBarky]

TrueNAS shouldn’t care where they are plugged into the sata ports.

[Ogrebear]

I have got the x2 drives that where offline back in the box and swapping the SATA cables have given the UNAVAIL disks in the pool back onlne.

How do I now get the pool back please? Is it using the Upgrade button which has become available?

[Ogrebear]

Upgrade option comes up with the message:

Upgrade Pool

Proceed with upgrading the pool? WARNING: Upgrading a pool is a one-way operation that might make some features of the pool incompatible with older versions of TrueNAS: AntecNAS

[Arwen]

If the previously failed disks are truly working again, then you need to import the pool from the GUI.

Do not upgrade the pool. This is something different that can prevent you from using an older version of TrueNAS, (and older version of ZFS).

[Ogrebear]

Under Import Pool the drop down is blank.

In shell I get:

truenas_admin@truenas[~]$ sudo zpool import
[sudo] password for truenas_admin:
pool: AntecNAS
id: 7002117372825943148
state: UNAVAIL
status: One or more devices contains corrupted data.
action: The pool cannot be imported due to damaged devices or data.
see: Message ID: ZFS-8000-5E — OpenZFS documentation
config:

    AntecNAS                                  UNAVAIL  insufficient replicas
      raidz1-0                                UNAVAIL  insufficient replicas
        977618a3-2d65-4b37-bdfd-9052136162e0  ONLINE
        0ced0fb0-b232-413b-8c60-ecd325a11a44  UNAVAIL
        bc82ff2e-9028-4d32-b269-896916639c4e  UNAVAIL
        8837ab81-6e7c-4778-8e83-6df850a5c256  ONLINE
        068b5935-6869-4df8-8f93-ee6b1f0bce80  ONLINE
        f7db8546-43d7-4b99-a04b-dec9b3ec0f2a  ONLINE

[neofusion]

So nothing has happened in terms of number of missing devices. However, which those two missing drives are has.

These used to be missing:
8837ab81-6e7c-4778-8e83-6df850a5c256
f7db8546-43d7-4b99-a04b-dec9b3ec0f2a

Now it’s:
0ced0fb0-b232-413b-8c60-ecd325a11a44
bc82ff2e-9028-4d32-b269-896916639c4e

Perhaps you have two ports that are bad.
Did you move them around? Did you swap cables around? Connect them to different ports on the motherboard?

Or, while you didn’t bring it up, but did you perhaps recently install a new NVMe or PCIe device in your system? Those can sometimes deactivate SATA-ports.

[Ogrebear]

I swapped the SATA’s for the ‘dead’ drives into other slots on the motherboard and those drives where then detected, but yes it seems I have x2 dead SATA slots on my Z170 board. BIOS sees all x6 slots, but only reads the drives in x4 of them, even if I swap working drives into said slots.

I have not changed anything on the machine since I built it.

I guess if the Pool will not import then it is game over?

[Fleshmauler]

@Ogrebear

I guess if the Pool will not import then it is game over?

I mean, I’d argue that if you can get all the drives detected on a working motherboard, that’d mean your pool & data are very likely fine. Might be time for an upgrade; or if you got a pcie slot available, you can grab a new (to you) HBA flashed to IT mode & use existing hardware.

[SmallBarky]

All your drives are probably fine and it is just two bad SATA ports.

I would make sure to download a backup of your system configuration.

What options do you have available to get all six data drives plugged in at the same time? Do you have another motherboard? HBA card? We need to know what options to suggest. Don’t panic

[Ogrebear]

I have flashed the BIOS on the machine and it is still not recognising the x2 SATA ports. Seems like they are dead. The other x4 are ok. TrueNAS still only sees the x4 drives.

I have started asking around to see if anyone has a machine with x6 SATA and an Nvme slot on. There seems to be a lot of x4’s out there. Also looking into a PCI-e SATA card which might be a way round the board problems.

[SmallBarky]

Find a HBA

What’s all the noise about HBA’s, and why can’t I use a RAID controller?

What's all the noise about HBA's, and why can't I use a RAID controller?

Multiply your problems with SATA Port Multipliers and cheap SATA controllers

Multiply your problems with SATA Port Multipliers and cheap SATA controllers

This resource was originally created by user: jgreco on the TrueNAS Community Forums Archive. Please DM this account or comment in this thread to claim it. In the last year or two, we’ve had a resurgence of users asking about SATA Port Multipliers and cheap SATA controllers. Please, do NOT use port multipliers, and use cheap SATA controllers only after extensive research. SATA controllers and SATA Port Multipliers are some of the cheapest hardware, designed to make a number of hard drives acc…

[Fleshmauler]

To add on to what barky is saying, a used hba will cost like $35 usd + the cost of a fan (gotta slap something ontop of them so they can be cooled).

Could be much cheaper than a new motherboard