On Tue, 2012-02-07 at 20:45 -0600, Derek McEachern wrote:
> I joined the mailing list shortly after Neil sent out a request for
> volunteer to update the nfs man page documenting the 'fsc'/'nofsc'
> options. I suspect this may stem from a ticket we opened with Suse
> inquiring about these options.
>
> Coming from a Solaris background we typically use the 'forcedirectio'
> option for certain mounts and I was looking for the same thing in Linux.
> The typically advice seems to be use 'noac' but the description in the
> man page doesn't seem to match what I would expect from 'forcedirectio',
> namely no buffering on the client.
>
> Poking around the kernel I found the 'fsc'/'nofsc' options and my
> question is does 'nofsc' provide 'forcedirectio' functionality?
No. There is no equivalent to the Solaris "forcedirectio" mount option
in Linux.
Applications that need to use uncached i/o are required to use the
O_DIRECT open() mode instead, since pretty much all of them need to be
rewritten to deal with the subtleties involved anyway.
Trond
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
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