Here's a great question from one of my partners:
"What are the pros and cons of using the built in MPIO driver (DSM) from Microsoft versus the NetApp MPIO?"
For some background on MPIO and DSMs, see James Burke's excellent post here:
http://blogs.netapp.com/whu_who/2007/12/introduction-to.htmlNow, to answer that question...
The Microsoft generic MPIO DSM (device-specific module) does not, by itself, have all the advantages of the NetApp Data ONTAP DSM for Windows MPIO. For example:
-- NetApp's MPIO DSM is more stable at lower levels of the I/O stack (not all vendors enumerate & uniquely identify devices the same way),
-- Improve performance by using NetApp's MPIO for an active/active LUN load balancing policies (Round Robin, Auto Assigned, etc.) ... thus, keeping track of IOs arriving order & sending the requests on the wire in the proper temporal order (extremely complex algorithm), &
-- NetApp MPIO also supports more granular (configurable) failover & path recovery for NetApp LUNs.
Microsoft's approach to licensing their MPIO kit to storage vendors (like NetApp, EMC, HP, etc.) keeps them out of the business of coding & testing all the different low-level APIs from each vendor.
Bottom-line: The generic Microsoft MPIO offers basic path redundancy, while NetApp's DSM for MPIO gives your customers greater performance, load-balancing, & failover capabilities.
Move over mouse & keyboard, meet the world of touchscreen storage management:
