From 292695531ae4019bb15deedc121b218d1908b648 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 27 Mar 2006 01:18:10 -0800 Subject: [PATCH] md: Final stages of raid5 expand code This patch adds raid5_reshape and end_reshape which will start and finish the reshape processes. raid5_reshape is only enabled in CONFIG_MD_RAID5_RESHAPE is set, to discourage accidental use. Read the 'help' for the CONFIG_MD_RAID5_RESHAPE entry. and Make sure that you have backups, just in case. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/Kconfig | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'drivers/md/Kconfig') diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index ac43f98062f..fd2aae150cc 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -127,6 +127,32 @@ 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 a version of mdadm newer than 2.3.1. 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 -- cgit v1.2.3