Hi everyone,
I recently expanded my RAIDZ1 and noticed that I’m missing some disk space afterwards.
The pool now consists of 3 × 16 TB HDDs. TrueNAS reports 14.55 TiB for each drive (sda, sdb, sdf).
I’ve included all the information I was able to gather.
Based on my calculations, I’m missing roughly 3–4 TiB.
What can I do to fix this?
Should I destroy the pool and create a new one? That would be problematic because I would need to restore all files from my backup, which would take a long time. During that time, I would have no backup available.
truenas_admin@nas[~]$ sudo zpool list
[sudo] password for truenas_admin:
NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
HDD 43.7T 24.2T 19.5T - - 0% 55% 1.00x ONLINE /mnt
truenas_admin@nas[~]$ lsblk -bo NAME,MODEL,ROTA,PTTYPE,TYPE,START,SIZE,PARTTYPENAME,PARTUUID
NAME MODEL ROTA PTTYPE TYPE START SIZE PARTTYPENAME PARTUUID
loop1 0 loop 419213312
sda ST16000NM001G-2KK103 1 gpt disk 16000900661248
└─sda1 1 gpt part 2048 16000898564096 Linux filesystem 2dbc82ed-4f67-4492-a4e4-d9782ab32062
sdb ST16000NM001G-2KK103 1 gpt disk 16000900661248
└─sdb1 1 gpt part 2048 16000898564096 Solaris /usr & Apple ZFS 8400203a-4662-42a3-a7bb-ec9b3143e958
sdc Samsung SSD 870 EVO 1TB 0 gpt disk 1000204886016
└─sdc1 0 gpt part 2048 1000203091968 Solaris /usr & Apple ZFS e8d5db77-ac61-4467-9e1c-49c2c3beecee
sdd Samsung SSD 870 EVO 1TB 0 gpt disk 1000204886016
└─sdd1 0 gpt part 2048 1000203091968 Solaris /usr & Apple ZFS 9e95b3b2-1227-448d-a9d6-b56ee6272b87
sde Samsung SSD 860 EVO 1TB 0 gpt disk 1000204886016
└─sde1 0 gpt part 2048 1000203091968 Solaris /usr & Apple ZFS b8e9bd17-b44d-4150-8f30-2538ea81705f
sdf ST16000NM001H-3KW113 1 gpt disk 16000900661248
└─sdf1 1 gpt part 2048 16000898564096 Linux filesystem 1a3d9de7-3f42-427a-b7dc-d1f87749dc4c
truenas_admin@nas[~]$ zpool status
pool: HDD
state: ONLINE
scan: scrub repaired 0B in 11:05:34 with 0 errors on Tue Dec 2 14:25:54 2025
expand: expanded raidz1-0 copied 24.1T in 1 days 07:44:50, on Tue Dec 2 03:20:20 2025
config:
NAME STATE READ WRITE CKSUM
HDD ONLINE 0 0 0
raidz1-0 ONLINE 0 0 0
2dbc82ed-4f67-4492-a4e4-d9782ab32062 ONLINE 0 0 0
1a3d9de7-3f42-427a-b7dc-d1f87749dc4c ONLINE 0 0 0
8400203a-4662-42a3-a7bb-ec9b3143e958 ONLINE 0 0 0
errors: No known data errors
