See Changelog

[nfs-utils.git] / utils / exportfs / exports.man

diff --git a/utils/exportfs/exports.man b/utils/exportfs/exports.man
index 5dcc809361d6002df79eb3f76b0f43392116b832..97264cdc6511880f69ed3d00a0c092043b1abffd 100644 (file)
--- a/utils/exportfs/exports.man
+++ b/utils/exportfs/exports.man
@@ -95,17 +95,31 @@ This can also be made explicit by using
 the
 .IR ro " option.
 .TP
 the
 .IR ro " option.
 .TP

-.IR sync
-This option requests that all file writes be committed to disc before
-the write request completes.  This is required for complete safety of
-data in the face of a server crash, but incurs a performance hit.
-The default is to allow the server to write the data out whenever it
-is ready.  This can be explicitly requested with the
-.IR async " option.
+.IR async
+This option allows the NFS server to violate the NFS protocol and
+reply to requests before any changes made by that request have been
+committed to stable storage (e.g. disc drive).
+
+Using this option usually improves performance, but at the cost that
+an unclean server restart (i.e. a crash) can cause data to be lost or
+corrupted.
+
+In releases of nfs-utils upto and including 1.0.0, this option was the
+default.  In this and future releases,
+.I sync
+is the default, and
+.I async
+must be explicit requested if needed.
+To help make system adminstrators aware of this change, 'exportfs'
+will issue a warning if neither
+.I sync
+nor
+.I async
+is specified.

 .TP
 .IR no_wdelay
 .TP
 .IR no_wdelay

-This option only has effect if
-.I sync
+This option has no effect if
+.I async

 is also set.  The NFS server will normally delay committing a write request
 to disc slightly if it suspects that another related write request may be in
 progress or may arrive soon.  This allows multiple write requests to
 is also set.  The NFS server will normally delay committing a write request
 to disc slightly if it suspects that another related write request may be in
 progress or may arrive soon.  This allows multiple write requests to