X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fmd%2FKconfig;fp=drivers%2Fmd%2FKconfig;h=ac25a48362acab47ea103fa176b39590ed5c2e42;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hp=ac43f98062fd104f03d29b1b0ee6b3d74bc0f690;hpb=cee37fe97739d85991964371c1f3a745c00dd236;p=linux-2.6.git

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index ac43f9806..ac25a4836 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -127,6 +127,33 @@ config MD_RAID5
 
 	  If unsure, say Y.
 
+config MD_RAID5_RESHAPE
+	bool "Support adding drives to a raid-5 array (experimental)"
+	depends on MD_RAID5 && EXPERIMENTAL
+	---help---
+	  A RAID-5 set can be expanded by adding extra drives. This
+	  requires "restriping" the array which means (almost) every
+	  block must be written to a different place.
+
+          This option allows such restriping to be done while the array
+	  is online.  However it is still EXPERIMENTAL code.  It should
+	  work, but please be sure that you have backups.
+
+	  You will need mdadm verion 2.4.1 or later to use this
+	  feature safely.  During the early stage of reshape there is
+	  a critical section where live data is being over-written.  A
+	  crash during this time needs extra care for recovery.  The
+	  newer mdadm takes a copy of the data in the critical section
+	  and will restore it, if necessary, after a crash.
+
+	  The mdadm usage is e.g.
+	       mdadm --grow /dev/md1 --raid-disks=6
+	  to grow '/dev/md1' to having 6 disks.
+
+	  Note: The array can only be expanded, not contracted.
+	  There should be enough spares already present to make the new
+	  array workable.
+
 config MD_RAID6
 	tristate "RAID-6 mode"
 	depends on BLK_DEV_MD