Reported size discrepancies

[AVB]

Running 8.3.1 with 6 3TB Seagate drives in a Z1 pool.
GUI shows 2.8TB available but when in the shell I get 3.79TB free with the zpool get free Media command. (Media is the name of my pool.)
Get size Media shows 16.2TB which is close to the 16.3TB the drives are listed at (2.72TB ea)
Get capacity Media shows 76%.
Get allocated Media lists 12.5TB which is well below the 13.6TB that I would think should be there (2.72TB * N-1 with N = to my 6 drives minus one parity drive)
Swap is only 12GB so that doesn't really account for much.
DOS reports 10.923TB used and 3.108TB free but those are binary values so they would be 9.943TB and 2.827TB in decimal which are pretty much in agreement with the GUI values shown.
My question is where is the difference between the 3.79TB the shell reports and the 2.8TB the GUI reports. Where is the missing 1TB and how do I reclaim it for use?

 

[AVB]

I'm not sure if I should be impressed I stumped the experts or worried I stumped the experts.

 

[cyberjock]

There's a whole laundry list of reasons why free space from one place isn't the same elsewhere. Dedup, compression, and what is determined as 'free' space and 'used' space is different depending on the tool. This has been discussed to death in the forums, hence nobody responded.

 

[AVB]

Thank you for the response. I've read a number of the threads but the discrepancy is within Freenas itself. The GUI says one thing and the shell says another. One would assume that they both should be looking at and reading the same thing. What I found odd was how DOS matched the GUI but not the shell. I would have thought it would be the other way around.

 

[cyberjock]

Thank you for the response. I've read a number of the threads but the discrepancy is within Freenas itself. The GUI says one thing and the shell says another. One would assume that they both should be looking at and reading the same thing. What I found odd was how DOS matched the GUI but not the shell. I would have thought it would be the other way around.

No, its' NOT like that.

Check this out.. do a df -h and check out your pool. Now do a zpool list. Here's mine...

Code:

[root@freenas] ~# df -h
Filesystem             Size    Used   Avail Capacity  Mounted on
tank                    23T    21T    1.5T    93%    /mnt/tank
[root@freenas] ~# zpool list
NAME  SIZE  ALLOC  FREE    CAP  DEDUP  HEALTH  ALTROOT
tank  32.5T  29.9T  2.59T    92%  1.00x  DEGRADED  /mnt

So there, I just showed you 2 totally different ways that from the command line you can get totally different numbers. So which one does the GUI use? What if I told you it was neither of those....

So yeah, you have to understand, thoroughly, what the given program is using to come up with those numbers. If you choose to use snapshots, dedup, compression, or zvols, you can expect even more confusion if you don't know how the program gets its final values.