Apple Xsan 1.4 - Manual (Page 25)

Chapter 1 Overview of Xsan 25
Storage Pools
LUNs are combined to form storage pools. A storage pool in a small volume might
consist of a single RAID array, but storage pools in many volumes consist of multiple
arrays.
Xsan distributes file data in parallel across the LUNs in a storage pool using a RAID 0
(striping) scheme. So, you can improve a client’s access speed by distributing available
storage over several LUNs in a storage pool.
You can set up storage pools that have different performance or recoverability
characteristics and assign folders to them using affinities. Users can then select where
to store files based on their need for speed or safety. See “Folders with Affinities” on
page 28.
The illustration on page 23 shows eight LUNs combined into two storage pools, one
pool consisting of RAID 0 (fast, but not recoverable) arrays and the other made up of
RAID 5 (not as fast, but recoverable) arrays. Xsan stripes data across the four LUNs in
each storage pool.
You use Xsan Admin to add available LUNs to specific storage pools.