NFS + cache coherence

But I still had some doubts

Hi
I'm writing an application to perioidcally transfer a set of files over
nfs to the another machine (and delete these files when am done)
[
environ
linux > 2.6
nfs v4
]
I'd some doubts

1. Does every fwrite (of the system page size say 4k) transfer the data
block immediately to the server?

2. Will the fclose() block until a response for COMMIT is recieved from
the server ? (i'm
avoiding an fsync after every write)
If it doesn't block then the client app has no way of knowing
whether the data has been actually sent across or not.

3. What am really concerned about is that once i've closed the file fd
does it guarantee
that the data has been successfully written over the server??

thanks!

On Fri, 08 Sep 2006 03:16:16 -0700, jon wayne rearranged some electrons to
form:


> 3. What am really concerned about is that once i've closed the file fd
> does it guarantee
> that the data has been successfully written over the server??
>
> thanks!

man sync

--
David M (dmacchiarolo)
http://home.triad.rr.com/redsled
T/S 53
sled351 Linux 2.4.18-14 has been up 8 days 12:22

jon wayne <(E-Mail Removed)> wrote:
> 3. What am really concerned about is that once i've closed the file fd
> does it guarantee that the data has been successfully written over
> the server??

It depends on the NFS mount. See "man 5 nfs", especially "noac", "actimeo"
(and friends). Sadly, none of this guarantees that the server has actually
flushed the data to its physical disks.

Chris