On 05/06/2015 03:02 PM, Kevin Jernigan wrote:
Mldaen,
The primary design goal for Direct NFS (dNFS) was / is to provide SAN-equivalent (or better) performance, in terms of both latency and throughput, while using NFS / Ethernet infrastructure. A secondary goal is to simplify the configuration and tuning process for Oracle Database with NFS storage. dNFS accomplishes these goals by implementing the NFS client inside Oracle Database, rather then using the OS-supplied "kernel" NFS client. This allows dNFS to skip some parts of the networking stack, and to skip some of functionality that is required for a general-purpose NFS client, such as write ordering. In addition, dNFS creates a separate connection to the NFS server for each Oracle process, unlike kNFS, which essentially multiplexes all the processes' I/O's through one or a very small number of connections to the NFS server. There are other optimizations in dNFS which provide major performance improvements over kNFS, and which allow dNFS to auto-configure itself based on interrogating the NFS server.
In general, if the NFS server can handle the workload, then dNFS can provide SAN or iSCSI-equivalent performance, with very little configuration work required of the DBA or system administrator.
