zfs/raidz: seems like I'm failing with math

[Eugene M. Zheganin]

Hi.

FreeBSD 11.0-RC1 r303979, zfs raidz1:

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# zpool status gamestop
   pool: gamestop
  state: ONLINE
   scan: none requested
config:

         NAME        STATE     READ WRITE CKSUM
         gamestop    ONLINE       0     0     0
           raidz1-0  ONLINE       0     0     0
             da0     ONLINE       0     0     0
             da1     ONLINE       0     0     0
             da2     ONLINE       0     0     0
             da3     ONLINE       0     0     0
             da4     ONLINE       0     0     0
             da5     ONLINE       0     0     0

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6 disks 960 Gbs each:

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# smartctl -a /dev/da0
smartctl 6.5 2016-05-07 r4318 [FreeBSD 11.0-RC1 amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Samsung based SSDs
Device Model:     SAMSUNG MZ7KM960HAHP-00005
Serial Number:    S2HTNX0H507466
LU WWN Device Id: 5 002538 c402bdac1
Firmware Version: GXM1003Q
User Capacity:    960 197 124 096 bytes [960 GB]
Sector Size:      512 bytes logical/physical

[...]

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But:

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# zpool list gamestop
NAME       SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP HEALTH  ALTROOT
gamestop  5,22T  4,38T   861G         -    24%    83%  1.00x ONLINE  -

===Cut===

Why 5.22T ? If zpool is displaying raw size, it should be 960 x 6 = 5760 
Gb = 5.65 T. If it's displaying the actual data, then it should be 960 x 
5 = 4800 Gb = 4.68 T. 5.22 T is neither of these. I'm stuck, please 
explain. :)


Thanks.

Eugene.