I would thank Kevin Closson for the insights the he gives on his blog. Recently i partecipated on a thread on comp.databases.oracle.server on a debate on Oracle ASM over NFS. After reading some “old” posts by Kevin Closson, starting from this and following all the links , it’s more clear to me what does it mean Oracle over NFS, that is Oracle with NAS and what are the advantages of using NAS over SAN. I’ve to say that Kevin refers to systems more complex than those with wich i normally work. He spokes about RAC systems with 10, 25, 50 100 nodes. I’ve never heard here in Italy about such systems.
There is no doubt that with such numbers manageability of NAS is superior of that of SAN, you save all FC cabling and related costs. On the other hand i’ve found difficult to think about a datacenter with such numbers (clusters with tens of nodes) and only one type of storage type for all (NAS). They (the datacenters) are frequently more like a mess of old and new technologies so i think there is no hope to reach such unified architecture.
I found interesting a post where Kevin Closson refers to a document of EMC where is a comparation of performance between Oracle with ASM on RAW devices, Oracle on NFS , Oracle with CFS and others (what about iSCSI?). I found interesting the observation that performance with ASM and direct I/O CFS are more or less the same.