3 x 4 tb in RaidZ1 = 10.9 TB???

[paul718]

i just set up a new system, (3) new WD Red 4 TB drives in an ITX case with an Asrock AM1B-ITX mobo & AMD Athlon 5350 w/ 1x8gb RAM (have since purchased a matching 8gb stick). No graphics card or other devices. The HDDs all passed badblocks write/compare plus SMART short and long tests prior to installing NAS4Free 11. Memory also passed 48 hours of Memtest86 with no errors prior to OS install.

Formatted each drive separately as a ZFS drive in the NAS4Free v11.0.0.4 GUI and then added them to a vdev and zpool using a RAIDZ1 array. Was shocked to see that 3x4TB yielded a 10.9TB array. i did neglect to check the "create 4k wrapper" box, but the ashift does appear to be 12, anyway.

Did a large RSYNC from an older NAS4Free box (v10) of a 929gb folder and it finished, eventually - claiming it was 1.33 TB on the new NAS.

At this point, I thought insufficient RAM at the initial vdev creation was the mistake - or the failure to tick the 4K wrapper box. I am not sure how to proceed, though. Do i destroy the zpool and vdev and rescan/reimport the HDD and start over with a fresh NAS4Free installation disk and 16 gigs of RAM? Am i able to simply reformat the HDDs using gpart destroy and then deploy some other solution? I have read lots of potential solutions but cannot determine the best path forward - any help will be greatly appreciated.

- Paul

[ms49434]

You can calculate the capacity of a hard drive in different ways.
The 2 most common numbering systems are based on the multiplication with 1,000 and based on the multiplication with 1,024.
your 4TB drive has a capacity of 4,000,000,000,000 Bytes, 3 of them make 12,000,000,000,000 = 12TB.
If you convert this number into a value based on 1,024 you'll get 10.9TiB. (TB stands for Terabyte and TiB stands for TebiByte).

there's no need to reformat your disks - you won't gain any more space.

You created a RAIDZ1 which means 1/3 of the available capacity in your configuration is used for redundancy.
you copied over 929GB of your data but your system is using 929GB / 2 * 3 = 1.39TB.

Everything is looking fine from my side.

[raulfg3]

ashift 12 is the recomended for new 4K disc
ashift 9 is the old ashift for old HD with 512 Bytes ( not KB).

once I say this, please read this articles:

https://forums.freebsd.org/threads/44197/

https://forums.freebsd.org/threads/34050/



and for the queestion of your post 3x4TB = 10,9TB is good,

4x10^12 / 1024 /1024 /1024 /1024 = 3,63TB real

3,63TB real data in each 4TB disc x 3 Disk ( 1 is lost in parity) = 10,91 TB available.

[paul718]

Thank you so much for the quick replies Raul & MS - I am thankful! I had thought that the reporting would show 3,63 * 2 = ~ 7.2 GB free total and not show the third disk's parity area as available space.