Note that his zpool is in "raidz" mode not "mirror" mode. The latter is going to be far better and faster at handling replacement of dead/dying drives because y

Note that his zpool is in "raidz" mode not "mirror" mode. The latter is going to be far better and faster at handling replacement of dead/dying drives because you can pretty much just remove the old one, plug the new one in and then update the zpool (in that order). It's also faster in normal use due to lack of performance issues related to calculating and storing of parity bits in raidz.