[CentOS] exports options

James Pearson james-p at moving-picture.com
Sun Mar 25 13:33:28 UTC 2007

On 24/03/07, Akemi Yagi <amyagi at gmail.com> wrote:
> I have been running a local repository on a CentOS4 server.  It serves
> CentOS4 clients (and FC5, FC6, and SuSE10.x if I bother to mention).  My
> current options for exports is (ro,wdelay,insecure,root_squash).  The ro
> and insecure options were added manually and others are default.  I
> understand 'sync' is the default although it is not shown by exportfs -v.
> I also found this description in the NFS FAQ:
> "For the Linux implementation of NFS Version 3, using the "async" export
> option to allow faster writes is no longer necessary. NFS Version 3
> explicitly allows a server to reply before writing data to disk, under
> controlled circumstances. It allows clients and servers to communicate
> about the disposition of written data so that in the event of a server
> reboot, a Version 3 client can detect the reboot and resend the data.
> In summary, be sure all exports on your Linux NFS servers use the "sync"
> option by setting it explicitly or by upgrading your nfs-utils package to
> version 1.0.1 or later. If you need fast writes, be sure your clients
> mount using NFS Version 3. You may also improve write performance by
> adding the "wdelay" option to your exports."
> In other words, the default settings (sync and wdelay) seem to be the best
> choice.  Is this generally true?  Are there any cases in which use of,
> for example, async is more desirable?

As you are exporting the file system read-only, then options that
effect the write performance aren't relevant ...

James Pearson

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