I would say ZFS would be a lot closer to NetApp.

For Isilon, a better comparison would be Ceph. With Ceph you can have a cluster of 10s or 100s of servers, and you can lose 1 disk, or 1 server, or 1 rack or servers and it will recover very quickly.

As long as your minimum requirements for your type of replication or erasure coding profile are satisfied, your data stays safe and available.