On 12/10/2012 08:11 AM, Paul Gideon Dann wrote: > I've been learning about the close-to-open policy of NFS, which causes each > file to be flushed to the server as it's closed, to ensure consistency across > clients. This is a big performance hit when trying to upgrade the system, > because of the numerous writes to small files. > > I know about the "async" export option, obviously, but there is also a "nocto" > client mount option, which is supposed to disable the close-to-open mechanism > for that client. As far as I can tell, this is supposed to stop the client > from flushing the file when it closes it (as well as not bothering to check > cache consistency when it opens). However, this seems to have no effect: the > client is still flushing the file to the server on close, causing massive > wait-io. > > Does anyone have any idea why "nocto" doesn't have the effect I was hoping it > would? The "async" option works as expected, but it's more important to me > that the client cache is correct, and it just bugs me. What NFS version are you using? I just took a quick glance through the code and from what I can tell, v2 and v3 check for the "nocto" flag but v4 doesn't. I'm not sure if this is an oversight or by design, but I can ask later today. - Bryan > > Thanks for any insight, > Paul
