FreeNas Total Pool Size

So I have a FreeNas box that has 29T 7.63T Allocated and 21.4T Free according to cli running zpool list -v . The GUI is showing available space 14.55TiB (27% used) . How and why are these numbers different? How come the GUI doesn’t show how big the pool is only available space? I might not be interpreting this correctly so I am looking for some clarification. Thanks

There is a TiB and a TB, they are different

What difference would that be? What does what stand for?

1 TiB = 1.099511627776 TB

TiB (tebibyte) multiple of 1024, TB (terabyte) multiple of 1000.

Not sure the difference between TB and TiB (or TiBi for that matter…) will account for the difference there. I have no idea what the issue is but…

29TB = 26.4(ish) TiB (total)
7.63TB = 7 TiB (used)
21.37TB = 19.4 TiB (free)

if 14.55 available is = 27% used then 14.55 = 73% of total so total = 20TiB

None of that adds up to a solution as far as I can see. The free space from the CLI is close to the total given in the GUI

Does FreeNas annex some space for snapshots / root / something else?
Could it be that the full ZFS pool is not being used by whatever is reporting in the GUI?

Yeah, or is something hitting a hard limit of 20TiB

So here is what I see. Someone help me understand this


Ok, I’m still talking from a point of significant ignorance on FreeNAS (as it’s been about 10 years since I last looked at it) but…
The GUI image seems to show that you are looking at “/mnt/<redacted>” and that “/mnt/<redacted>” has 14.55TiB available. So per my maths previously is talking about a 20TiB slice of disk (5.45 used).

The zpool list command seems (to me) to be showing that “/mnt” is 29T (not sure if that is TB or TiB) with 7.63T used.

So my question, is /mnt in the CLI the same as “/mnt/<redacted>” in the GUI. My suspicion is that (and I don’t know the FreeNAS terms here) you created an array of disks called “/mnt” and then created a pool on that array which is called “/mnt/<redacted>” and that the array is 29TB in size whilst the pool is only (only!!) 20TiB

Thanks for clarifying I’m not sure how I missed that now it makes sense! Lastly ZFS has overhead; is the 14.55 TiB actual usable and the overhead is already deducted or is some percentage of the 14.55 TiB going to be needed for any overhead and I wont be able to use all of it.

–Lastly I want to add 2-3 SSD’s for some random shares and testing. I don’t want them in any raidz or mirror is that possible in freenas?


No idea sorry. Anyone else?