On Sat, 28 Jun 2014 05:01:00 +0200 George Duffield
[off-list ref] wrote:

quoted

quoted

quoted

changing the value to 0.500:
# echo 0.503 > /sys/block/md0/md/safe_mode_delay

makes no difference to the array state.

What if you write a smaller number?  e.g. 0.1

No change to array state.

quoted

What does /sys/block/md0/md/array_state show?

Funnily enough, it shows Clean

Ahh - I found it.
In get_array_info() in drivers/md/md.c:

	if (mddev->in_sync)
		info.state = (1<<MD_SB_CLEAN);
	if (mddev->bitmap && mddev->bitmap_info.offset)
		info.state = (1<<MD_SB_BITMAP_PRESENT);


that last line should be "|=".

Because you have a bitmap, the 'clean' state is being hidden.

Though if you have a bitmap, the 'clean' state isn't really important because
the bitmap knows which regions are 'clean' and which are not.

But it should be fixed.  I'll send a patch next week.

Thanks for persisting.

NeilBrown