Answering the first question.
Yes, the performance metrics is calculated on random request distribution.
About the second question.
In ZFS the performance is scaling on a vdev and not on a disk group level.
So, for example the stripe is populated on vdevs, and therefore the best performance can be achieved with the disks used as singles, but there won't be any redundancy of course.
The next performance tier would be to use mirror groups, so we have a redundancy on 1 disk in a group.
More complicated raidz's are giving a better redundancy with the cost of a performance.
Reply With Quote