9.3 Documentation error about using using disks of differing sizes in a pool
Almost at the bottom of this section: http://doc.freenas.org/9.3/freenas_intro.html#zfs-primer
It is recommended to use drives of equal sizes. While ZFS can create a pool using disks of differing sizes, the capacity will be limited by the size of the smallest disk.
I think this should be:
It is recommended to use drives of equal sizes in a vdev. While ZFS can create a vdev using disks of differing sizes, the capacity will be limited by the size of the smallest disk.
My understanding is that a pool is made up of vdevs and not disks, so I don't see how it makes sense to talk about disks in the context of a pool.I also base this on the following articles about ZFS:
- http://arstechnica.com/information-technology/2014/02/ars-walkthrough-using-the-zfs-next-gen-filesystem-on-linux/ - shows how all space will be used in the pool even if the vdevs are of differing sizes.
- http://jrs-s.net/2015/02/06/zfs-you-should-use-mirror-vdevs-not-raidz/ - explains how you can increase size in a pool by increasing the size of vdevs separately, leading to vdevs of differing sizes.
There's a lot of contradicting information about ZFS online, so I think it is important to correct this.
Thanks for a great product!