I'm thinking about using a hardware raid array with ZFS, using a single disk
vdev zpool. I want the ability to add/remove disks to an array, and I'm
still unsure of the stability of zfs as a whole. I'm looking for an easy
way to resize and manage disks that are greater than 2 terabytes.
If I have a single block device, /dev/da0, on my system that is represented
by a zfs disk vdev, and the size of this block device grows (because the
underlying hardware raid expands), will zfs correctly expand? And will it
correctly expand in place?
In theory, this works fine - I have never tried it myself. The only
other way to expand a zpool is by adding more vdevs: You cannot change
a vdev once it is created other than to take it from a single disk to a
Sun's ZFS best practice guide states that you should avoid a single disk
vdev because performance on the whole suffers and is worse than UFS.
I am going to publish some benchmark figures soon to back this up, based
on testing I did with a 16 disk hardware RAID6. ZFS was *alot* faster
when I gave it the disks in a RAIDZ2 vdev.