That should be the same, it's the pool identifier. Assuming it still mounts normally with zpool import zmain, you can try to move some of the data to another pool/disk to see if you can get the VDEs capacity below 100%, at least like 95%.

Okay. I can also try deleting some files I no longer need if the delete operation works this time.

I can confirm deletes work now. Would it be quicker to run a balance operation?

I should also admit that I don't know how to move things around in a ZFS pool. Unless you meant, copying things to a new pool.

4 minutes ago, Chukwuka13 said:

Would it be quicker to run a balance operation?

ZFS doesn't have a full balance like btrfs, though they now have a rewrite command, that can help if there are no snapshots.

It may be easier to try and get the vdevs to below 95% deleting or moving some data outside the pool. That would be my recommendation for now, any new writes to the pool should go to the new vdev.

If you want to try rewriting, I would only do it on a small dataset/folder without snapshots to start with:

zfs rewrite -r /mnt/zmain/path/to/smalish/folder/or/dataset

Okay, I assume you meant moving existing data from zmain to a new pool or drive. I can do that first.

 Hmm, I went ahead and tried to re-add the pool like last time, only to see the import fail due to a cannot import with misplaced devices errorL

Dec 30 18:08:11 Nebula emhttpd: zmain: recover volume
Dec 30 18:08:11 Nebula emhttpd: /sbin/blkid /dev/sdbf1 2>&1
Dec 30 18:08:12 Nebula emhttpd: /dev/sdbf1: LABEL="zmain" UUID="9455508329953933197" UUID_SUB="12874290684355378790" BLOCK_SIZE="4096" TYPE="zfs_member" PARTUUID="493f0da2-3976-45eb-bdfa-af47502b1280"
Dec 30 18:08:12 Nebula emhttpd: zmain: zfs recover pool
Dec 30 18:08:12 Nebula emhttpd: shcmd (15980): /usr/sbin/zpool import -f -m -N   -d /dev/sdbf1 -d /dev/sdbg1 -d /dev/sdbh1 -d /dev/sdbi1 -d /dev/sdbj1 -d /dev/sdbk1 -d /dev/sdbl1 -d /dev/sdbm1 -d /dev/sdbn1 -d /dev/sdbo1 -d /dev/sdbu1 -d /dev/sdbv1 -d /dev/sdbw1 -d /dev/sdbx1 -d /dev/sdby1 -d /dev/sdbz1 -d /dev/sdca1 -d /dev/sdcb1 -d /dev/sdcc1 -d /dev/sdcd1 -d /dev/sdce1 -d /dev/sdcf1 -d /dev/sdcg1 -d /dev/sdch1 -d /dev/sdci1 -d /dev/sdcj1 -d /dev/sdck1 -d /dev/sdcl1 -d /dev/sdcm1 -d /dev/sdcn1 -d /dev/sdco1 -d /dev/sdcw1 -d /dev/sdcx1 -d /dev/sdcy1 -d /dev/sddc1 -d /dev/sddd1 -d /dev/sdde1 -d /dev/sddf1 -d /dev/sddg1 -d /dev/sddh1 -d /dev/sdcp1 -d /dev/sdcz1 -d /dev/sdcq1 -d /dev/sdcv1 -d /dev/sdcr1 -d /dev/sdct1 -d /dev/sdcu1 -d /dev/sdda1 -d /dev/sdbt1 -d /dev/sddb1 9455508329953933197 zmain
Dec 30 18:08:12 Nebula sSMTP[2977652]: Sent mail for [email protected] (221 2.0.0 closing connection 46e09a7af769-7cc667ec367sm23272126a34.23 - gsmtp) uid=0 username=root outbytes=760
Dec 30 18:08:55 Nebula emhttpd: zmain: zfs verify devices
Dec 30 18:08:55 Nebula emhttpd: /usr/sbin/zpool status -P zmain 2>&1
Dec 30 18:08:55 Nebula emhttpd:   pool: zmain
Dec 30 18:08:55 Nebula emhttpd:  state: ONLINE
Dec 30 18:08:55 Nebula emhttpd:   scan: scrub repaired 27.3M in 8 days 03:08:01 with 0 errors on Thu Dec 11 03:08:02 2025
Dec 30 18:08:55 Nebula emhttpd: config:
Dec 30 18:08:55 Nebula emhttpd: 	NAME            STATE     READ WRITE CKSUM
Dec 30 18:08:55 Nebula emhttpd: 	zmain           ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	  raidz2-0      ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbf1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbg1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbh1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbi1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbj1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbk1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbl1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbm1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbn1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbo1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	  raidz2-1      ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbu1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbv1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbw1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbx1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdby1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbz1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdca1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcb1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcc1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcd1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	  raidz2-2      ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdce1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcf1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcg1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdch1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdci1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcj1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdck1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcl1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcm1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcn1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	  raidz2-3      ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdco1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcw1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcx1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcy1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sddc1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sddd1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdde1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sddf1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sddg1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sddh1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	  raidz2-4      ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcp1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcz1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcq1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcv1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcr1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdct1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdcu1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdda1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbt1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sddb1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	  raidz2-5      ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdak1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: zmain: import: misplaced device: sdak1
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdab1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: zmain: import: misplaced device: sdab1
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdaf1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: zmain: import: misplaced device: sdaf1
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbs1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: zmain: import: misplaced device: sdbs1
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdai1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: zmain: import: misplaced device: sdai1
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdac1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: zmain: import: misplaced device: sdac1
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdbq1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: zmain: import: misplaced device: sdbq1
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdao1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: zmain: import: misplaced device: sdao1
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdad1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: zmain: import: misplaced device: sdad1
Dec 30 18:08:55 Nebula emhttpd: 	    /dev/sdaj1  ONLINE       0     0     0
Dec 30 18:08:55 Nebula emhttpd: zmain: import: misplaced device: sdaj1
Dec 30 18:08:55 Nebula emhttpd: errors: No known data errors
Dec 30 18:08:55 Nebula emhttpd: zmain: cannot import with misplaced devices
Dec 30 18:08:55 Nebula emhttpd: shcmd (15981): /usr/sbin/zpool export -f zmain

It looks like the import command Unraid used did not consider the 10 new drives we added. I'm still able to manually import by running zpool import zmain though. Seems like the Unraid config still has the old pool data saved somewhere.

Okay, a reboot (possibly also the update I performed to 7.2.3 from 7.2.2 during the reboot) appears to have resolved the issue. Unraid now successfully mounts the pool on array start. Sincerely, I appreciate all the help you've provided in helping me resolve this issue.

Make sure you now avoid filling the pool over 90%, you can set a reservation, if you think that may happen accidentally.

6 hours ago, JorgeB said:

Make sure you now avoid filling the pool over 90%, you can set a reservation, if you think that may happen accidentally.

This is the Minimum free space setting under the pool settings right?

4 minutes ago, Chukwuka13 said:

This is the Minimum free space setting under the pool settings right?

That will work; you can also set a reservation in ZFS, but that would need the CLI.

Okay, it looks like the Minimum free space setting was reset to 0 zero after the re-import. I'll need to fix that.