Grow: Stop bothering about md driver versions older than 0.90.00

[thirdparty/mdadm.git] / mdadm.8.in

diff --git a/mdadm.8.in b/mdadm.8.in
index 1e4f91d8cc26115e0fa1b5782079e4000fd50e2a..744c12b534bfe43b34fb4bd673a50613723b060a 100644 (file)
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -126,7 +126,7 @@ of component devices and changing the number of active devices in
 Linear and RAID levels 0/1/4/5/6,
 changing the RAID level between 0, 1, 5, and 6, and between 0 and 10,
 changing the chunk size and layout for RAID 0,4,5,6,10 as well as adding or
-removing a write-intent bitmap.
+removing a write-intent bitmap and changing the array's consistency policy.
 
 .TP
 .B "Incremental Assembly"
@@ -724,7 +724,9 @@ When creating an array on devices which are 100G or larger,
 .I mdadm
 automatically adds an internal bitmap as it will usually be
 beneficial.  This can be suppressed with
-.B "\-\-bitmap=none".
+.B "\-\-bitmap=none"
+or by selecting a different consistency policy with
+.BR \-\-consistency\-policy .
 
 .TP
 .BR \-\-bitmap\-chunk=
@@ -1015,6 +1017,45 @@ simultaneously. If not specified, this defaults to 4.
 Specify journal device for the RAID-4/5/6 array. The journal device
 should be a SSD with reasonable lifetime.
 
+.TP
+.BR \-\-symlinks
+Auto creation of symlinks in /dev to /dev/md, option --symlinks must
+be 'no' or 'yes' and work with --create and --build.
+
+.TP
+.BR \-k ", " \-\-consistency\-policy=
+Specify how the array maintains consistency in case of unexpected shutdown.
+Only relevant for RAID levels with redundancy.
+Currently supported options are:
+.RS
+
+.TP
+.B resync
+Full resync is performed and all redundancy is regenerated when the array is
+started after unclean shutdown.
+
+.TP
+.B bitmap
+Resync assisted by a write-intent bitmap. Implicitly selected when using
+.BR \-\-bitmap .
+
+.TP
+.B journal
+For RAID levels 4/5/6, journal device is used to log transactions and replay
+after unclean shutdown. Implicitly selected when using
+.BR \-\-write\-journal .
+
+.TP
+.B ppl
+For RAID5 only, Partial Parity Log is used to close the write hole and
+eliminate resync. PPL is stored in the metadata region of RAID member drives,
+no additional journal drive is needed.
+
+.PP
+Can be used with \-\-grow to change the consistency policy of an active array
+in some cases. See CONSISTENCY POLICY CHANGES below.
+.RE
+
 
 .SH For assemble:
 
@@ -1139,6 +1180,8 @@ argument given to this flag can be one of
 .BR no\-bitmap ,
 .BR bbl ,
 .BR no\-bbl ,
+.BR ppl ,
+.BR no\-ppl ,
 .BR metadata ,
 or
 .BR super\-minor .
@@ -1279,6 +1322,16 @@ option will cause any reservation of space for a bad block list to be
 removed.  If the bad block list contains entries, this will fail, as
 removing the list could cause data corruption.
 
+The
+.B ppl
+option will enable PPL for a RAID5 array and reserve space for PPL on each
+device. There must be enough free space between the data and superblock and a
+write-intent bitmap or journal must not be used.
+
+The
+.B no\-ppl
+option will disable PPL in the superblock.
+
 .TP
 .BR \-\-freeze\-reshape
 Option is intended to be used in start-up scripts during initrd boot phase.
@@ -1291,6 +1344,10 @@ Reshape can be continued later using the
 .B \-\-continue
 option for the grow command.
 
+.TP
+.BR \-\-symlinks
+See this option under Create and Build options.
+
 .SH For Manage mode:
 
 .TP
@@ -2144,8 +2201,10 @@ in the array exceed 100G is size, an internal write-intent bitmap
 will automatically be added unless some other option is explicitly
 requested with the
 .B \-\-bitmap
-option.  In any case space for a bitmap will be reserved so that one
-can be added layer with
+option or a different consistency policy is selected with the
+.B \-\-consistency\-policy
+option. In any case space for a bitmap will be reserved so that one
+can be added later with
 .BR "\-\-grow \-\-bitmap=internal" .
 
 If the metadata type supports it (currently only 1.x metadata), space
@@ -2284,9 +2343,11 @@ superblock field in the subarray.  Similar to updating an array in
 .B \-U
 or
 .B \-\-update=
-option.  Currently only
-.B name
-is supported.
+option. The supported options are
+.BR name ,
+.B ppl
+and
+.BR no\-ppl .
 
 The
 .B name
@@ -2297,6 +2358,13 @@ re\-assembled.  If updating
 would change the UUID of an active subarray this operation is blocked,
 and the command will end in an error.
 
+The
+.B ppl
+and
+.B no\-ppl
+options enable and disable PPL in the metadata. Currently supported only for
+IMSM subarrays.
+
 .TP
 .B \-\-examine
 The device should be a component of an md array.
@@ -2630,6 +2698,8 @@ RAID0, RAID4, and RAID5, and between RAID0 and RAID10 (in the near-2 mode).
 .IP \(bu 4
 add a write-intent bitmap to any array which supports these bitmaps, or
 remove a write-intent bitmap from such an array.
+.IP \(bu 4
+change the array's consistency policy.
 .PP
 
 Using GROW on containers is currently supported only for Intel's IMSM
@@ -2786,6 +2856,16 @@ can be added.  Note that if you add a bitmap stored in a file which is
 in a filesystem that is on the RAID array being affected, the system
 will deadlock.  The bitmap must be on a separate filesystem.
 
+.SS CONSISTENCY POLICY CHANGES
+
+The consistency policy of an active array can be changed by using the
+.B \-\-consistency\-policy
+option in Grow mode. Currently this works only for the
+.B ppl
+and
+.B resync
+policies and allows to enable or disable the RAID5 Partial Parity Log (PPL).
+
 .SH INCREMENTAL MODE
 
 .HP 12