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authorNeilBrown <neilb@suse.de>2010-07-07 13:35:07 +1000
committerNeilBrown <neilb@suse.de>2010-07-07 13:35:07 +1000
commit3d5279b0534a8d9e95681a0e495b000691a2582b (patch)
treea05f19ebcabad013e65a5638eb4b284c149a61d5 /mdadm.8.in
parent0ad6835c98fd3968d998cf9f3e1d88bdf7ec4a76 (diff)
downloadmdadm-3d5279b0534a8d9e95681a0e495b000691a2582b.tar.gz
Improve --re-add documentation
and add the fact that --test can now be used with --manage operations. Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'mdadm.8.in')
-rw-r--r--mdadm.8.in54
1 files changed, 39 insertions, 15 deletions
diff --git a/mdadm.8.in b/mdadm.8.in
index 78db335..8094009 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -1011,25 +1011,49 @@ homehost to match the current host.
.SH For Manage mode:
.TP
+.BR \-t ", " \-\-test
+Unless a more serious error occurred,
+.I mdadm
+will exit with a status of 2 if no changes were made to the array and
+0 if at least one change was made.
+This can be useful when an indirect specifier such as
+.BR missing ,
+.B detached
+or
+.B faulty
+is used in requesting an operation on the array.
+.B \-\-test
+will report failure if these specifiers didn't find any match.
+
+.TP
.BR \-a ", " \-\-add
-hot-add listed devices. For arrays with redundancy, the listed
-devices become available as spares. If the array is degraded, it will
-immediately start recovering data on to one of these spares.
+hot-add listed devices.
+If a device appears to have recently been part of the array
+(possibly it failed or was removed) the device is re-added as describe
+in the next point.
+If that fails or the device was never part of the array, the device is
+added as a hot-spare.
+If the array is degraded, it will immediately start to rebuild data
+onto that spare.
+
+Note that this and the following options are only meaningful on array
+with redundancy. They don't apply to RAID0 or Linear.
.TP
.BR \-\-re\-add
-re\-add a device that was recently removed from an array. This is
-normally only needed for arrays that have be built (i.e. with
-.BR --build ).
-For created arrays, devices are always re\-added if that is possible,
-however using \-\-re\-add will ensure the device isn't made into a
-spare if the \-\-re\-add failed.
-
-When re\-adding a device, if nothing has changed on the array since the
-device was removed, no recovery is performed. Also, if the array has
-a write-intent bitmap, then the recovery performed after a re\-add will
-be limited to those blocks which, according to the bitmap, might have
-changed since the device was removed.
+re\-add a device that was previous removed from an array.
+If the metadata on the device reports that it is a member of the
+array, and the slot that it used is still vacant, then the device will
+be added back to the array in the same position. This will normally
+cause the data for that device to be recovered. However based on the
+event count on the device, the recovery may only require sections that
+are flagged a write-intent bitmap to be recovered or may not require
+any recovery at all.
+
+When used on an array that has no metadata (i.e. it was built with
+.BR \-\-build)
+it will be assumed that bitmap-based recovery is enough to make the
+device fully consistent with the array.
If the device name given is
.B missing