Dell Dustin,   You can mix RAID levels and drive types in the same pool.  That is supported.  Especially on current FW 7.1.5 and 8.0.2 was just released today in fact.    When there are multiple members in the same pool, the data is striped across the members, proportionally to their relative sizes.  So the 15K member will only have a smaller amount of the data compared to the others.    Often when you purchase a 15K member it's with a specific purpose in mind.  Some of the benefit of the faster spindle will be lost since more of the volume data will be on the slower/larger members.    You can set the volume preference to R10 to request that more of the volume goes there.  You may want to start with the 15K in its own pool.  Later you can merge the pools.    If you are happy with your performance now, and aren't planning on greatly increasing the I/O load then you can keep them in the same pool and it will performance much better overall.  Since the array members work together.    Additionally, during a peak sustained load, the Advanced Performance Load Balancer will exchange blocks from a very busy member to a less busy one.  This helps even out the load.    Regards,   Don 
We purchased a PS4100x a couple of years ago and have it set for RAID6. We've been happy with the performance, but we are running out of storage space. We recently acquired a PS6000e and PS4000xv that we are looking to add to the default storage pool and provide us more storage capacity. I was able to successfully join the PS4000xv to the pool as a RAID10 (performance benefit) and want to join the PS6000e to the pool as a RAID6 (capacity benefit). I've read several different posts about problems mixing RAID levels and drive types (SAS/SATA) and it negatively impacting SAN performance or outright causing SAN failure. Furthermore, I keep finding reference to issues with prior firmware. Unfortunately, I can't find anything current that will help me through this issue. My goal is to have the following 3 EqualLogic arrays in the default storage pool: Any help or guidance would be incredibly appreciated. Thank you!
Question about multiple arrays in a single storage pool