Is there any good documentation on storage pools and how they interact with drives and with volumes? The reason I ask is I have 8 spinny drives in my small cluster. When I do a DD read from the drives, the all around around 125 - 130 MB/sec (one the Western Digital Red runs up to 160 MB/sec) However two of the drives run at only 80 MB/sec. Are those two drives, because of inclusion in a storage pool now severely hampering my performance? How do determine which drives are in which pools, and which volumes are on which pools or am I completely misunderstanding this? There isn't much documentation about this in general.