See Changelog

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

diff --git a/utils/exportfs/exports.man b/utils/exportfs/exports.man
index 87fd50ec2f714d91a730fc1c56d421b59936a7b4..97264cdc6511880f69ed3d00a0c092043b1abffd 100644 (file)
--- a/utils/exportfs/exports.man
+++ b/utils/exportfs/exports.man
@@ -58,7 +58,7 @@ contiguous mask length (for example, either `/255.255.252.0' or `/22' appended
 to the network base address result in identical subnetworks with 10 bits of
 host). Wildcard characters generally do not work on IP addresses, though they
 may work by accident when reverse DNS lookups fail.
-.TP
+'''.TP
 '''.B =public
 '''This is a special ``hostname'' that identifies the given directory name
 '''as the public root directory (see the section on WebNFS in
@@ -95,17 +95,31 @@ This can also be made explicit by using
 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
-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