NACK
4 devs is actually the mandatory minimum for raid6;
minimum of 2 data stripes plus 2 devices for parity and q-syndrome.
FWIW: the 2 devices minimum for the raid4/5 layouts are correct too,
because those personalities are able to drive 2 devices as raid1
(i.e. allow for takeover from raid1 with 2 legs)
in order to reshape them to 'real' raid4/5 by adding N>0 devices
Heinz
On 10/28/2015 07:50 PM, Andy Grover wrote:
A raid6 device can be created from 3 devs. This previously didn't cause
an error because minimal_devs was not being checked.
Signed-off-by: Andy Grover <agrover@xxxxxxxxxx>
---
drivers/md/dm-raid.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 5941cfd..1ded052 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -90,9 +90,9 @@ static struct raid_type {
{"raid5_ra", "RAID5 (right asymmetric)", 1, 2, 5, ALGORITHM_RIGHT_ASYMMETRIC},
{"raid5_ls", "RAID5 (left symmetric)", 1, 2, 5, ALGORITHM_LEFT_SYMMETRIC},
{"raid5_rs", "RAID5 (right symmetric)", 1, 2, 5, ALGORITHM_RIGHT_SYMMETRIC},
- {"raid6_zr", "RAID6 (zero restart)", 2, 4, 6, ALGORITHM_ROTATING_ZERO_RESTART},
- {"raid6_nr", "RAID6 (N restart)", 2, 4, 6, ALGORITHM_ROTATING_N_RESTART},
- {"raid6_nc", "RAID6 (N continue)", 2, 4, 6, ALGORITHM_ROTATING_N_CONTINUE}
+ {"raid6_zr", "RAID6 (zero restart)", 2, 3, 6, ALGORITHM_ROTATING_ZERO_RESTART},
+ {"raid6_nr", "RAID6 (N restart)", 2, 3, 6, ALGORITHM_ROTATING_N_RESTART},
+ {"raid6_nc", "RAID6 (N continue)", 2, 3, 6, ALGORITHM_ROTATING_N_CONTINUE}
};
static char *raid10_md_layout_to_format(int layout)
--
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