56 lines
2.0 KiB
Diff
56 lines
2.0 KiB
Diff
From 2551061c253b8fd45ee93d1aab3e91d2c7ac9c20 Mon Sep 17 00:00:00 2001
|
|
From: Coly Li <colyli@suse.de>
|
|
Date: Mon, 24 Feb 2020 12:34:09 +0100
|
|
Subject: [RHEL7.9 PATCH 62/77] mdadm.8: add note information for raid0 growing
|
|
operation
|
|
|
|
When growing a raid0 device, if the new component disk size is not
|
|
big enough, the grow operation may fail due to lack of backup space.
|
|
|
|
The minimum backup space should be larger than:
|
|
LCM(old, new) * chunk-size * 2
|
|
|
|
where LCM() is the least common multiple of the old and new count of
|
|
component disks, and "* 2" comes from the fact that mdadm refuses to
|
|
use more than half of a spare device for backup space.
|
|
|
|
There are users reporting such failure when they grew a raid0 array
|
|
with small component disk. Neil Brown points out this is not a bug
|
|
and how the failure comes. This patch adds note information into
|
|
mdadm(8) man page in the Notes part of GROW MODE section to explain
|
|
the minimum size requirement of new component disk size or external
|
|
backup size.
|
|
|
|
Reviewed-by: Petr Vorel <pvorel@suse.cz>
|
|
Cc: NeilBrown <neilb@suse.de>
|
|
Cc: Jes Sorensen <jsorensen@fb.com>
|
|
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
|
|
Cc: Wols Lists <antlists@youngman.org.uk>
|
|
Cc: Nix <nix@esperi.org.uk>
|
|
Signed-off-by: Coly Li <colyli@suse.de>
|
|
Signed-off-by: Jes Sorensen <jsorensen@fb.com>
|
|
---
|
|
mdadm.8.in | 6 ++++++
|
|
1 file changed, 6 insertions(+)
|
|
|
|
diff --git a/mdadm.8.in b/mdadm.8.in
|
|
index 5d00faf..a3494a1 100644
|
|
--- a/mdadm.8.in
|
|
+++ b/mdadm.8.in
|
|
@@ -2768,6 +2768,12 @@ option and it is transparent for assembly feature.
|
|
.IP \(bu 4
|
|
Roaming between Windows(R) and Linux systems for IMSM metadata is not
|
|
supported during grow process.
|
|
+.IP \(bu 4
|
|
+When growing a raid0 device, the new component disk size (or external
|
|
+backup size) should be larger than LCM(old, new) * chunk-size * 2,
|
|
+where LCM() is the least common multiple of the old and new count of
|
|
+component disks, and "* 2" comes from the fact that mdadm refuses to
|
|
+use more than half of a spare device for backup space.
|
|
|
|
.SS SIZE CHANGES
|
|
Normally when an array is built the "size" is taken from the smallest
|
|
--
|
|
2.7.5
|
|
|