Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff

[linux-2.6.git] / drivers / md / Kconfig

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index ac43f98..ac25a48 100644 (file)
--- 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