zfs capacity

[Gerrit Kühn]

Hi,

I just tried these two raidz2 setups with 36 disks: 3x 10+2, 4x 7+2.
The result is a bit puzzling for me, because I get the same capacity,
although one setup is using 6 drives for redundancy, the other is using 8:


---
root at pt-storage2:~ # zpool create data raidz2 gpt/disk-00 gpt/disk-01
gpt/disk-02 gpt/disk-03 gpt/disk-04 gpt/disk-05 gpt/disk-06 gpt/disk-07
gpt/disk-08 gpt/disk-09 gpt/disk-10 gpt/disk-11 raidz2 gpt/disk-12
gpt/disk-13 gpt/disk-14 gpt/disk-15 gpt/disk-16 gpt/disk-17 gpt/disk-18
gpt/disk-19 gpt/disk-20 gpt/disk-21 gpt/disk-22 gpt/disk-23 raidz2
gpt/disk-24 gpt/disk-25 gpt/disk-26 gpt/disk-27 gpt/disk-28 gpt/disk-29
gpt/disk-30 gpt/disk-31 gpt/disk-32 gpt/disk-33 gpt/disk-34 gpt/disk-35

root at pt-storage2:~ # zfs list
NAME   USED  AVAIL  REFER  MOUNTPOINT
data   695K   241T   201K  /data


root at pt-storage2:~ # zpool create data raidz2 gpt/disk-00 gpt/disk-01
gpt/disk-02 gpt/disk-03 gpt/disk-04 gpt/disk-05 gpt/disk-06 gpt/disk-07
gpt/disk-08 raidz2 gpt/disk-09 gpt/disk-10 gpt/disk-11 gpt/disk-12
gpt/disk-13 gpt/disk-14 gpt/disk-15 gpt/disk-16 gpt/disk-17 raidz2
gpt/disk-18 gpt/disk-19 gpt/disk-20 gpt/disk-21 gpt/disk-22 gpt/disk-23
gpt/disk-24 gpt/disk-25 gpt/disk-26 raidz2 gpt/disk-27 gpt/disk-28
gpt/disk-29 gpt/disk-30 gpt/disk-31 gpt/disk-32 gpt/disk-33 gpt/disk-34
gpt/disk-35

root at pt-storage2:~ # zfs list
NAME   USED  AVAIL  REFER  MOUNTPOINT
data   695K   241T   201K  /data
---


These are 10TB drives, so the numbers for the 3 vdev setup appear to be way
too low. Any ideas what is going on there?


cu
  Gerrit