From 8d6fac0087e538173f34ca7431ed9b58581acf28 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 2 Mar 2018 22:56:53 +0100 Subject: btrfs: add support for 4-copy replication (raid1c4) Add new block group profile to store 4 copies in a simliar way that current RAID1 does. The profile attributes and constraints are defined in the raid table and used by the same code that already handles the 2- and 3-copy RAID1. The minimum number of devices is 4, the maximum number of devices/chunks that can be lost/damaged is 3. There is no comparable traditional RAID level, the profile is added for future needs to accompany triple-parity and beyond. Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/btrfs/ctree.h') diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index aa1b437fb951..923a8804ae94 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -57,9 +57,9 @@ struct btrfs_ref; * filesystem data as well that can be used to read data in order to repair * read errors on other disks. * - * Current value is derived from RAID1C3 with 3 copies. + * Current value is derived from RAID1C4 with 4 copies. */ -#define BTRFS_MAX_MIRRORS (3 + 1) +#define BTRFS_MAX_MIRRORS (4 + 1) #define BTRFS_MAX_LEVEL 8 -- cgit v1.2.3-59-g8ed1b