|author||NeilBrown <email@example.com>||2006-03-27 01:18:10 -0800|
|committer||Linus Torvalds <firstname.lastname@example.org>||2006-03-27 08:45:01 -0800|
[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 <email@example.com> Signed-off-by: Andrew Morton <firstname.lastname@example.org> Signed-off-by: Linus Torvalds <email@example.com>
Diffstat (limited to 'drivers/md/Kconfig')
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index ac43f98062fd..fd2aae150ccc 100644
@@ -127,6 +127,32 @@ config MD_RAID5
If unsure, say Y.
+ bool "Support adding drives to a raid-5 array (experimental)"
+ depends on MD_RAID5 && EXPERIMENTAL
+ 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.
tristate "RAID-6 mode"
depends on BLK_DEV_MD