zfs pool different sizes reported

[m_l_s]

Hey, I hope anyone might be able to help and point me in the right direction to solve the following issue.

I have a zfs-pool in my machine which I use for mass storage. While I knew I was running low on storage, I expected to still have a few gigs available. But when I tried to rename a file on the pool I got an out of Storage error: (/Data2 is the pool MP)

$ touch /Data2/tst
touch: cannot touch '/Data2/tst': No space left on device

Upon looking in the Web-interface it still said I have ~135Gb left, so I took a closer look and discovered the following:

$ df -h /Data2/

Filesystem      Size  Used Avail Use% Mounted on

Data2           7.9T  7.9T     0 100% /Data2

$ zpool get capacity,size,health,fragmentation

NAME   PROPERTY       VALUE     SOURCE

Data2  capacity       98%       -

Data2  size           10.9T     -

Data2  health         ONLINE    -

Data2  fragmentation  34%       -

Somehow du and zpool report significantly different capacities and uses. I expect zpool/the web-interface to be correct, because the Pool consists of 2 12T drives and was created with exactly those drives.

How can I maybe use my last bit of storage?