8x3TB raidz2 showing 15.0 TB volume size, is this right?

[Royce Rezendes]

Quick question, I have just created a new raidz2 volume using 8x3TB drives and it is showing 15.0 TB size volume. I'm assuming it has something to do with 3TB drives actually being something like 2.7 TB? So, 8x2.7 is 21.6, then subtract 5.4 (2.7x2) = 16.2 TB. There's still a lot of space unaccounted for, any clarification would be wonderful.

 

[DifferentStrokes]

Sounds about right. Remember that ZFS reserves disk space for overhead.

 

[Bidule0hm]

Yep, it's normal.

A 3 TB drive is a 2.73 TiB drive and as we usually use TiB for size, space, files, ... it's misleading (and it's one purpose; marketing and co...).

Then you have some overhead from ZFS.

 

[Starpulkka]

@Royce Rezendes
Please fix you post TB. As an example 3TB HDD is actually like 2.7TiB.

Calculator says 8x3TB=16.4TB=14.9157131 TiB
also here is some intresting read at block sizes https://forums.freenas.org/index.ph...liability-calculator.28191/page-2#post-195915