With btrfs, we can't really put the log on a separate device. What we can do however is mirror the metadata across two devices and make the data striped across all devices. When we turn on dmerror then the metadata can fall back to using the other mirror while the data errors out. Note that the current incarnation of btrfs has a fixed 64k stripe width. If that ever changes or becomes settable, we may need to adjust the amount of data that the test program writes. Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> --- common/rc | 2 ++ 1 file changed, 2 insertions(+) diff --git a/common/rc b/common/rc index 83765aacfb06..078270451b53 100644 --- a/common/rc +++ b/common/rc @@ -830,6 +830,8 @@ _scratch_mkfs() ;; btrfs) mkfs_cmd="$MKFS_BTRFS_PROG" + [ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \ + mkfs_cmd="$mkfs_cmd -d raid0 -m raid1 $SCRATCH_LOGDEV" mkfs_filter="cat" ;; ext3) -- 2.9.4