On Mon, Dec 15, 2008 at 3:26 PM, Neil Brown <neilb@xxxxxxx> wrote: > On Monday December 15, jnelson-linux-raid@xxxxxxxxxxx wrote: >> According to the manpage for mdadm, --write-mostly can only be used >> add build, create, or add time. How does one set write-mostly devices >> *after* they've been added? > > You cannot. > The easiest approach is to remove it and re-add it with the > write-mostly flag. OK. However, why does fiddling with the /sys/block/mdX/dev-someDevice/state seem to do it? >> Why doesn't --examine-bitmap show the right mode? > > What were you expecting? The bitmap never reports anything about > writemostly, only write-behind. Yes, I was expecting write-behind. D'oh! >> Also, removing the bitmap from the array does not zero out the bitmap >> on the actual device. Shouldn't it do that? > > No. It simply records in the array metadata that there is no bitmap. > It might be sensible to get "--examine-bitmap" to report that the > bitmap is not active in some way. I'd like to offer my perspective on that - I feel as though when bitmaps are removed from arrays that the actual bitmap data should be zeroed (or marked as invalid somehow). What we have is a situation wherein a device that has never had a bitmap will say more or less just that when queried. However, a device that has had a bitmap at *any* point in the past (provided it's not been overwritten) will display that bitmap, no matter how crazy it is. -- Jon -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
