[SOLVED] Cannot create zfs pool because "is in use and contains a unknown filesystem"

[jesco_t]

Hi.

I searched around and none of usual suspects can fix this for me. Maybe you can help me. It's my homelab, so even if I have to reinstall stuff, it's no big issue.

I have a PBS with 1TB SSD SATA disks. Previously, I had a zfs pool on one of the disks which contained a datastore. I wanted to convert the pool into a mirror by adding a second 1TB disk. There's a slight size mismatch in the disks (one is 1.02TB, the other 1.0TB), so I decided to destroy the original pool and recreate it as a mirror.

My first step was to destroy the datastore and then the pool with

proxmox-backup-manager datastore remove backups
zpool destroy backups

I wiped the disk and created a new GPT table in the GUI.

Then I want to create the new mirror pool

zpool create tank ata-SanDisk_SSD_PLUS_1000GB_25232T801635 ata-INTENSO_SSD_1642312010000189
/dev/disk/by-id/ata-INTENSO_SSD_1642312010000189 is in use and contains a unknown filesystem.

Most of what I can find says to check for multipath configurations. I checked with "multipath -ll" and got no output (which I read as no multipath configuration stored). I checked if the disk somehow appears in the LVM with "pvs" and "vgs" to no avail.

What else can I check?

 

[Impact]

Please share lsblk -o+FSTYPE,MODEL. This should give us an overview of your storage.

 

[jesco_t]

There it is:

NAME         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS FSTYPE      MODEL
sda            8:0    0 119.2G  0 disk                         INTENSO SSD
├─sda1         8:1    0  1007K  0 part                         
├─sda2         8:2    0     1G  0 part /boot/efi   vfat       
└─sda3         8:3    0 118.2G  0 part             LVM2_member
  ├─pbs-swap 252:0    0     4G  0 lvm  [SWAP]      swap       
  └─pbs-root 252:1    0  99.5G  0 lvm  /           ext4       
sdb            8:16   0 953.9G  0 disk                         INTENSO SSD
sdc            8:32   0 931.5G  0 disk                         SanDisk SSD PLUS 1000GB

 

[jesco_t]

Hmm, I got it working. But I in now way understand why.

I tried to create a single disk pool with the offending INTENSO drive and strangely this worked. I destroyed the pool and then tried doing a mirror and got the same error. I then went and created a 2-disk stripe with both disks (after destroying the pool) and it worked. So I destroyed it once again and alas, when I tried to create a 2-disk mirror it worked (had to use -f of course, due to the mismatch in size, zpool complained with a helpful error message that time).

I am not sure what's to learn from this... :/

 

[news]

don't use unknown knowledge to use zfs.
use enterprise ssds with the same size, or add two partition with same size.
So you can build a zfs mirror on that.

Read the openZFS manual first.

 

[jesco_t]

don't use unknown knowledge to use zfs.
use enterprise ssds with the same size, or add two partition with same size.
So you can build a zfs mirror on that.

Read the openZFS manual first.

This is my homelab (as I wrote). It sees little throughput, a few gigabytes per week. So I will most certainly not waste money on enterprise SSDs. Always keep your application in mind!

I surprisingly fixed my problem a few minutes after posting. Just wanted to give the feedback so nobody spends any brain on something that’s solved for me.

Can a mod please lock this topic? Thank you.