One more comment on caching in NFS.
On 2016-12-29 12:06, I wrote:
Just a comment: race conditions over NFS can be common and severe if you construct a piece of SW (a system) which inherently assumes perfect [client] Cache Coherence. This is not really possible to achieve, and client side caching is VERY important, yes crucial, for performance of any distributed file system like NFS is.
The reason Oracle related NFSv3 mounts can work and perform with client side attr caching turned off (actimeo=0 / noac), is that Oracle controls things internally itself and caches states and data ways that satisfy its particular specific workload patterns over NFS.
So Oracle takes care of the performance in its own way, one can say. The NFS client doesn't have to do it.
(Oracle even has its own NFS client stack one can use, it's called something like DNFS I think, I may remember wrong)
/M