diff options
Diffstat (limited to 'utils')
| -rw-r--r-- | utils/exportfs/exports.man | 32 |
1 files changed, 23 insertions, 9 deletions
diff --git a/utils/exportfs/exports.man b/utils/exportfs/exports.man index 5dcc809..97264cd 100644 --- 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 -.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 |